Genre - sandboxy PvP/RvRvR medieval fantasy MMORPG with engine able to handle massive (and I mean MASSIVE) battles and sieges. And of course, with Goblins. Lots of Goblins.
Story - The story in these, it's us! Friends, enemies, guilds, epic or ridiculous or fun fights and moments people tend to create much better than pre-arranged stories do.
Art Style - I'd mix Warhammer Online's with Revival, Age of Conan (fatalities! <3) and maybe a very light touch of WoW in some aspects, especially the beasty races I love(d...). Another idea would be to make a crossover of The Journey + Ori and the Blind Forest ambients with some surrounding and characters of Gigantic!? Or maybe...No, wait, i better stop here :)
Combat - Warhammer Online meets Age of Conan meets GW2 meets WoW meets Camelot Unchained meets Gigantic, I'm really indecisive about top preference - in fact I'd surely enjoy a number of crossovers between these. Of course, building/housing and full destruction with physics and collision detection is a must.
Developer - Old Mythic with Mark Jacobs, the Warhammer team (but no EA please) or City State Entertainment or ArtCraft Entertainment.
While waiting for that perfect game to happen, I'll conclude with couple scenes from the best game ever made so far:
...or 
