I hated the mechanics they introduced with Shogun 2. Rome 2 is better than Shogun 2, but not as good as the original Rome TW or TW Medieval. I haven't played Rome 2 in so long I forgot mods are available.
Oh okay. I actualy really enjoy Shogun 2 but then again I'm a sucker for medieval themed Japan. I def prefer it over vanilla Rome 2. Despite all the patches, fixes and dlcs it still feels like a very dull game with a pretty makeup. Like the combat is incredibly dull and too fast for me. Only recently they introduced family trees, a feature that should have been part of it from the very beginning.
I highly recommend you try Divide et Impera. It turns the game into an 'actual' Rome 2. You'll feel right back at home.
If you also happen to have Attila, there is a great medieval mod in the making called 'Medieval Kingdoms Total War'. Currently it's only custom battles but there are plenty of factions already done, incredibly historicaly authentic, and they are working on a campaign. It looks great ! I'd keep my eye on that one.