Total War: Rome 2
I think I read this right; you're wondering what mods are possible with R2? Massive wall of text is hard to read.
Pack file manager (community modding tools) is already R2 enabled and pretty much finished besides maybe one or two areas.
R2 mods: www.twcenter.net/forums/forumdisplay.php?1990-Total-War-Rome-II-Mod-Threads
Steam doesn't have much of an effect with modding this game, besides .exe changes.
CA are planning to release modding tools and make it the most mod friendly game of the series. Shame that the release was so bad and modders are mainly fixing problems at the moment....
EDIT: as far as owning the game goes, with respect, DON'T. Not yet at least, it is a mess and will put you off. Look for Angry Joe's Review, it's the most accurate I've seen. Wait for patches.
[Edited by chikawowwow, 9/14/2013 9:11:35 AM]