In MTW the dismounted cavalry couldn't become cavalry again after they dismounted. :O

There will have to be some guns. And since they're not as advanced as the guns in ETW or NTW they won't be the end all of battle quite yet lol. XD So cavalry and infantry will still do good against them. If the environment is a bid variable like in the original STW that would be cool. So then your Yumi Samurai would beat the poor gunners who are operating at 50% effectiveness or less. XD Yumi archers will also be able to use rugged land to their advantage better.

I'm thinking if gunpowder was like it was in MTW 2 Total War that would be okay. It'd be a factor for sure. That way the player could do like Nobunaga at Nagashino. I doubt the AI would. I also doubt the player vs. player would become dominated by guns. But it's hard to tell. I dunno.

I like guns, and since they played such a role in the Sengoku they should be present in some form. Napleonic armies in the Sengoku would just be ridiculous though.... XD I think it will play out okay. :D