I won't be tackling my suggestions in order because there is kind of a natural order to them and I didn't put them in that order when I formulated the list. Really, the first thing I need to talk about is a top to bottom skill tree rewrite.
To start with, in order to make a skill tree and make the skills and the upgrades attached to those skills work well, you need to have a basic idea of what you want a skill to do. So let's start by dividing skills into three categories: active skills, investment skills and extras.
Active skills are ones that allow you to actively create value while you are playing. Investment skills are ones that allow you to earn value when you are not playing, or to passively earn value while playing. Extras do not earn you value in the game.
What we need, then, is to make a formal decision regarding how you much earn by being active and how skills affect that, as well as how much you earn by investing and how skills affect that. We also need to agree that extras are extras.
I'm also going to add a fourth category of skill that isn't currently in the game: augmenting skills. An augmenting skill is one that makes another skill do something that it didn't used to do.
So, what should these values be? Well, based on current game mechanics, I would say that for simplicity's sake we can set the value for active skills at 30 per second and the value of investment skills at around 2000 per hour. You may wonder about what units I am using, I intentionally left them out. For the purposes of this exercise we'll be using quoin method of evaluating resources, where 1 energy, 1 currant and 1 imagination (before mood bonus) are all interchangeable with one another. This system of evaluation is basically internally inconsistent, but that's okay. The fact that different people will actually value energy, currants and imagination differently is fine. Also, I am ignoring mood completely; either it will be replaced by a completely new system or it will continue to be irrelevant as it is now.
So how would we actually earn our 30 per second? We could do it the same way we do it now using Animal Kinship VII - but we'd be able to do it using any other comparable skill investment. So here are the active skills:
Animal Kinship, Animal Husbandry, Fox Brushing, Soil Appreciation, Light Green Thumb, Botany, Arborology, transmutation skills, Jellisac Handling, Bog Specializiation, cooking skills, Alchemy, Intermediate Admixture, Tincturing, Potionmaking, meditation skills, Mining, Refining, Smelting, Tinkering, Fiber Arts, Furniture Making
Right now you get very different results by using these different skills. The results are somewhat proportional to the number of skills it takes to get those results in most cases, but not in all cases.
The revamp would change this. We would set the approximate value per second that could be attained by learning a particular number of skills. If we use Animal Kinship as the current model (and ditch the side prerequisites) we could say that seven skills achieves the maximum result. So if you invest seven skills in an active activity - as well as purchasing relevant upgrade cards - then you get 30 value per second by doing those active skills. So the new animal kinship skills would look like this:
Not different than the old animal kinship except for my notes about the value. So how would we achieve that value? Well first of all we need some kind of estimate of how often we get to harvest from an animal. For this we should take into account walk and load time. Basically it takes about 35 seconds to walk a street. In an animal rich area we should see in the neighborhood of 20 animals per street. It could be more, and in many places right now it is less, but as I've argued in the past, balance isn't actually all that necessary, we just have to ballpark it.
So if animal interactions take about two seconds each then we want them to be worth about 112.5 currants per second. It is not a coincidence that this is about what they are worth now since I chose Animal Kinship as the basis of this exercise (a piggy gives you two harvest of 4 meat plus two 10% chances of 20 more meat for 12 meat plus 20 imagination minus 4 energy for a total value of about 136, more than 112 but in the right ballpark - chickens give a little less). The value of actions at lower levels would need to be adjusted.
For example, at the first rank of animal kinship I want to increase the value of animal interactions to about 3 per second. Currently at this rank it takes about 7 seconds to interact with an animal which means the reward for doing so should be around 8.75. Currently its more like 5, so that could use some improvement, but that's easy to do by tossing a couple of imagination in.
So a few minor adjustments could make animal kinship come out to the framework that I've come up with (which we know to be absolutely ideal - I know that I said the reader should add their own disclaimers to insert humility into the mix, but in this case I'm exactly right; the numbers given above couldn't be better and are in no way subjective).
What about the other animal skills? Well, Herdkeeping is an extra, it confers no economic benefits. Animal Husbandry, on the other hand, is a top end crafting skill. Since it is top end, we want it to convey 30 value per second and to have at least six prerequisites. So lets get rid of the bizarre requirement to have Soil Appreciation 2 to get Herdkeeping and making Animal Husbandry require Animal Kinship 5 and Herdkeeping. There's also Remote Herdkeeping, but that's an investment skill so we'll talk about that a bit later.
What about Fox Brushing? Here is where we have to do something sneaky. The prerequisite for Fox Brushing will be Animal Kinship, but we'll need to add a little extra text to the skill: "A fiber-hunter with the skill of Fox Brushing can expect to rub foxes the right way (rather than the wrong one), reaping a handful more fibers with every brush. The higher your rank of Animal Kinship, the more impressive your Fox Brushing will be." This is our first example of an augmenting skill. Fox Brushing, rather than actually doing anything itself, really modifies Animal Kinship so that Animal Kinship improves your interactions with foxes as well as with chickens, piggies and butterflies.
While we are putting in augmenting skills, let's add a few more to round out the animal skill tree. We can have Batterfly Feeding, Sloth Rocking, Crabbiness, and Firefly Charming. Each one makes Animal Kinship affect your interactions with those animals so that you get more guano, more snails, more currants and imagination and more of something for each animal type respectively (note that crabbiness is an investment skill, not an active skill, and that firefly charming would have to add in some new kind of reward for doing it, like giving you imagination or something, though collecting fireflies is already really good per second return if you do it right).
But Animal Kinship was easy to do because I base my expectations around it. What about other active skills? First of all, they are going to need seven ranks. That doesn't necessarily mean that they directly need seven ranks, but it should take seven skills to get to the top. In the case of Arborology, I think this means eliminating the prerequisites for Arborology rank one, making Light Green Thumb an augmenting skill that make Arborology improve petting and watering as well as harvesting, giving Arborology seven ranks, and making the transmutation skills augmenting skills as well - you transmute at maximum effectiveness only if you have maximum arborology. Stick on an augmenting skill for paper trees as well. Most likely the amount of crop received from each tree will have to be varied based on the value of the crop (you shouldn't receive the same number of beans as you do general vapour when beans are worth one fifth as much).
Soil Appreciation can have seven ranks and Jellisac Handling and Bog Specialization can both be augmenting skills for it. Remember that the seventh rank of Soil Appreciation should give 30 value per second. That means that if it takes two seconds to dig from a pile and you can dig five times a day then the average value of a digging a pile should be 470. In order to achieve that they'd probably have to add some kind of random rewards (I recommend treasure boxes that have a verb "Open" that destroys them and gives you currants, gems or other special money items).
Mining similarly needs more ranks. Remarkable mining four is not very much better than it should be currently if it was converted to the new system (we could pretty much leave it how it is and add three more ranks that all improve mining).
Meditation needs some work too, but at maximum rank should be giving you 15 energy and 15 imagination per second you meditate (again, I'm just ignoring mood completely here).
We don't have to make everything boring and same-y, but we can shoot for a general consistency across the different skills.
These are the skills that let you accumulate value passively even when you aren't playing the game. The investment skills are Remote Herdkeeping, Croppery, Herbalism, Distilling, and the machine using skills (well, the machine using skills are kind of an odd hybrid - I'd make them investment skills).
As I said, the target here is around 2000 currants per hour. Right now Remote Herdkeeping and Herbalism are right around that mark. Croppery and Distilling are not. Of course some of these have more requirements than others, so it might make sense for them to vary (but I think Croppery needs a boost).
Unlike active skills, investment skills are cumulative (with the possible exception of herbalism and croppery which don't stack well). If you have more than one then you get to benefit from all of them. That means that optimal way to choose your skills is to choose as many of these as you can and focus on a single active skill to make money while you are playing. The payoff for doing so isn't that astounding though. 2000 currants and hour is only a little over half a currant per second. The richest of the rich aren't going to be the richest of the rich because they took more of these skills, they are going to be rich because they play more or make good trades.
On the current skills tree the extras are: Herdkeeping, Nudgery, Master Gardener (sort of), Element Handling, Levitation, Martial Imagination, Piety, Penpersonship, Bureaucratic Arts, Eyeballery, Teleportation, and Engineering.
Sometimes these skills could be useful placeholders to be prerequisites of other skills. Other times they are just plain extra and if you want them you have to pay a skill for them even though they don't provide you with economic benefits.
A Sample Skill Tree
In the end, I see a skill tree that looks something like this:
The following tree shows the prerequisites:
And finally this tree is colour coded to show the function of each skill:
It turns out the lines at a little blurry between my skill types, which is a good thing, I think. You may read some of this, such as the creation of new skills or the increased ranks of Bureaucratic Arts as a flight of fancy, but it is actually the one true way to save the game from disaster of a magnitude so great that it will not only cause the game to collapse but will also cause the deaths of millions around the world.