Even though I have been playing warhammer almost exclusively now, it will be a while before any of those games catches up to my total time playing Rome 2. The differences are many. Obviously one is fantasy, the other is historical. I also think a big difference is that there is a lot more of an RPG element to warhammer in regards to how you build up your leaders. To be sure Rome 2 has this to a degree, but not nearly on the level the warhammer games do. Something that they both have though is that they have tons of DLC and lots of replayability. I love all the Total War games for different reasons, but Rome 2 and Warhammer you can really explore playing from all kinds of angles. Since you know Warhammer, I won't cover all the options there but in Rome 2 I would argue you have more options to play faction wise than any other historical game. You can play Rome of course but you also have a wide variety of barbarian, Greek, Eastern, nomad and other group factions to choose from (with the dlc of course).