I really hope they don't continue the "streamlining" trend that a lot of the newer, big game titles seem to be following. I wish they get close to Medieval 2 than Shogun 2, and that they actually allow modding since that's half the reason the old Total War titles are so great. As any enthusiast will know, there are mods both for R:TW and M:TW that can, without hyperbole, be said to be almost on the same level as expansion packs (generally lacking only in the kind of polish that requires paid professionals or access to the source to pull off).
I must admit my hopes are not high. The last several times I had high hopes for a sequel I was deeply diappointed by the streamlining watering-down the gameplay into a prettier-looking, but shallower, copy of the old one, often with features removed rather than added; replaced with the dumb-ing down of game mechanics for... commercial reasons, I guess.
Beyond that basic stuff, what I wish they'd change (from Shogun 2) is to put the significant random character traits back in, and give them meaning (not just "oh he drinks a lot and fucks any woman he sees so your army moves slower"). In Shogun 2 every character is basically a carbon-copy of every other character. In R:TW and M:TW, the individual characters had, well, character, at least in my mind. When every character ends up being the same they may as well not be there at all.
I guess they could also just add some way of gaining traits that doesn't involve combat, but I really wish they don't do it in the form of a boring, streamlined 'talent tree' - since then every character'd be the same, boring, uninspired cookie-cutter again.
