Hey, so, little suggestion (maybe random). I don't know if something like this was brought up previously (I don't really think I can handle reading 253 pages of comments XD), but why not extend on the idea of the Grottol? I have 2 main ideas.
1, making the Grottol have various forms (for axe and shovel), kind of just to complete the sort of 'tool trio' already in the game (cause hoes are not harvesting tools).
Maybe they could have different behaviours depending on the form, e.g. instead of just running and burrowing, the sand one could drop a pile of sand on you, and if successful, could then run away, our the wood one would block your path with trees or something, or they could just run away.
2, same concept, just making them their own mob.
I completely understand if you find this redundant, as it literally is just a copy and paste for the most part (not literally of course, but you know what I mean), but then, because of that, it could just be a little something to add, which shouldn't be too difficult for you! I just feel like the Grottol is one of the most forgettable for me, so having a sort of trio, I think would make it more interesting!
Sorry, but this isn't what I'm looking for. I just feel like it would make the original grottols feel less special if you could encounter other versions of there elsewhere. Other features are coming for grottols that will make them more exciting.
You can use the configuration file to modify their spawns however you want.
How have they been messing with your farms?