Yeah, the only thing I can see this set up doing is making your own dwellers take longer to move about. The invaders already move left to right, top to bottom fighting in each room as they go anyways. Even if you design it so they have to move all the way to the bottom on the right to go up all the way on the left to the first room on the second floor, it's not like you will be able to take pot shots as they run across. Your people don't fight unless that room is their destination.
Other than having your highest level people closest to the top floor in the first 3 rooms they fight and armed with the best weapons you can get, I don't see any real "strategy." That isn't even really strategy as the same method is used in all cases. Strategy suggests that there are different things you could do in different cases for better effect.
The only real room strategy I can think of that would be any benefit would be checker boarding your rooms so that no two rooms are adjacent. In this case if a room is empty or if an event gets out of hand in one, the event won't kill off your entire vault.
This game needs some work before I can honestly say that there is any real strategy involved. One correct strategy does not a strategy game make.