(I almost posted this in the bugs section, as this is actually a bug.)
New worms spawning in a compost bin are 0% purity, no matter what.
1.) They should have the exact same purity as the humus spawning.
2.) the higher the "worm efficiency" is, the less frequent worm spawns should be.
Right now you basically have to sit at your compost and watch them 24/7, didnt the devs say something about less grind and so on?! This would be an easy place to start.
[edit:]
In addition, anyone ever did something that required 2 different tools?
Like removing tree stumps and feeding the logs as wood choppings into a compost bin?
Having to switch tools all the time is just stupid, either have the game auto equip the best tool for whatever action you start, or have the game use the best tool without equipping it.
It is as well stupid that you cant switch the item in the cursor (in your hand) with any item currently equipped, that is just odd and either a bug or something to annoy players, in any case its stupid, so fix this **** please! -.-
[edit2:]
You may as well look again at the execution time and humor drain of several activities, some are hindering the player for no reason.
Like 0.5 phlegm per tile paved, or how you have to "destroy" things that you build yourself on your own property (claim) like someone who tries to smash it!
It would already make the game a slight bit more fun if things like chopping woodblocks/boards, baking, ... would be considerably faster.
There should be a action "disassemble" that can be only used on thing that are on you own claim or unclaimed, that does it 10 times as fast and returns some of the materials used.
As an example, this would still not fix the nonsense of constantly rebuilding your compost bins to make good compost, but it would help a tiny bit, and you could re-arrange your walls easier.
[edit3:]
2 humus for a field, and whole 3 humus for a gardening pot, seriously?
Oh, and why do you actually need to make wood choppings off of wood blocks before you can put them into the compost?! I boldly claim that it would not only make sense, but it would make a lot of people happy if you could put them there directly.