As odd as it may sound coming from someone who backed Kingdom Come, I actually really like fantasy games, so I hope there are a few good fantasy mods. Personally, I would like to see at least one Warhammer Fantasy mod, and maybe a Warmachine and/or Malifaux mod. I'd make one for Malifaux, myself, if the modding tools were going to be released on linux (I haven't touched a copy of Windows since 2006, and I personally think I'm better off for it). Maybe I'll be able to get them working in Wine.
I backed this game mostly because I love the idea of open world RPGs, but think that Skyrim and Oblivion are equally shallow, pathetic examples of what an open world RPG should be. The realistic historical setting isn't a bad thing, but I will admit that I hate playing as a human (I play one of those selfish pieces of filth in real life, why would I ever want to play one in a game?) and mostly just want to create a character that subdues and eventually destroys the human race.
I think, first and foremost, I look forward to a monsters mod that adds small outbreaks of vampirism or lycanthropism. I want to create a character named Kain, become a vampire, raise an order of vampires to rule the world (and herd humans as cattle), defeat the seraphim knights and raise them to be my leutenants, then throw my right-hand-man into a pit of hellfire when he evolves faster than me. Then I want to travel through time, luring Raziel (the lieutenant that I threw into the pit of hellfire) to important historical points to shape his understanding of the world, and eventually use Raziel's soul (bound to a gigantic kriss-like sword) to defeat the elder god that gave Raziel his powers.
... Now I'm imagining a remake of the entire Legacy of Kain series, using modern graphics and Kingdom Come's combat system. Something like that would make me so happy. I'm going to go to bed thinking about that, in the hope that it ends up part of my dreams.