I'm sure this has been suggested somewhere in here, (not reading 227 pages) but I think a "Monster Hunter inspired" mod would be amazing. I'm not saying we rip that game off, but something like it. Including monsters and other fantasy creatures could be very interesting if done right, if it's even possible. The basic ideas I had were:
1.) The mod is inspired by Monster Hunter, so creatures we could fight could range from dinosaurs (raptors, T-Rex, even some non-hostile herbivores maybe) to real life "creatures" (Wolves, bears, deer). Of course, some fantasy creatures would be in as well. Dragons, wyverns, centaurs, anything cool.
2.) After fighting the creatures, the loot screen would give obvious "loot" like meat and bones; but hides, scales, claws, teeth and other parts could be gathered from certain creatures. They could have varying qualities and be sold for a good price if you get a high quality item. Maybe there could even be a way to "craft" items based off the creature. Maybe some secret smith has a list of weapons and armor that you "trade" certain items for.
3.) Creatures operate like bandits, in a sense. They have no faction standing and can attack anyone. Some monsters, like dragons, may even attack villages or even castles and cities.
4.) Quests could be included that relate to hunting down certain monster groups. They could operate just like the "find the group of bandits" quests. Nothing special, but fun.
5.) Change to the skill system. I played one mod that had the "Power" skills (Draw, Strike, Throw) and "shield" removed. I liked this because I always hated how your shields magically got stronger, in a sense, just because of a skill. I prefer the game to be based off my skill, more than my characters.
6.) In addition to #5, maybe a "Beast Slaying" skill could be included. It would sort of be a combo of a few existing skills, tweaked to fit this mod. Each rank includes: + 5% damage to creatures. Maybe the ability to capture them like normal troops and +5/10/20, some number, to your hold limit. And maybe at certain ranks you can even "recruit beast prisoners" and use them as troops, or like the riding skill, be able to use them as mounts. Higher skill requirement for better creatures.
I have some other ideas, but this has gone on for a while. Plus, I have no idea if any of this is even possible to make, much less if anyone would be interested in trying to. If anyone else is truly interested in this, I can come up with more stuff later.