Good AI. First, foremost, and always. Since I'm not interested in the setting or gun-based battles, this is the clincher for me. I can overlook a lot of things if a game has smart AI.

My other main hope is that it manages to do a good job in capturing the feeling of a dramatically changing world. I find watching the world sprint towards modernity strangely addictive in Victoria II, despite hating the setting. I don't expect the same level of social and economic depth from FotS, obviously, yet I think the game should be able to portray the rapid shift in technology levels, ideas, and social structure. One of the previews mentioned social tension and resistance to change and I hope that means something more engaging than rebel stacks spawning.

After that ... just give me a worthy continuation of Shogun 2. Tight design, meaningful strategic choices, atmosphere.

Faster load times would be a bonus.