The reason I say that Tannhauser is really a miniatures game is because the game would play exactly the same if the figures were replaced with tokens. There is no physical terrain or objects that matter at all to the game. This has been true of many 'miniature' games of late - Star Wars Minis, Heroclix, etc. I love the figures, but this is a board game.
Have a look at a map and seriously think about the rooms and how many people the pathfindings allow in there. I think it is correct. You are not going to have 20 soldiers packed into a living room. The Paths make the map clearer, more open, and more fun. I like them.
The Bull Rush needs to be changed and the grenade rule needs to be changed. For grenades, you should not be able to aim at a circle occupied by your own troops, but otherwise you should be able to target an occupied space. Maybe you make a roll and if you miss, your opponent gets to move it to an adjacent circle. Or something, but you should be able to toss a grenade into a crowded hallway.
Some kind of overwatch would also be good - to spend your action in order to wait to use your action.