I really do like the raider interaction of the game. I just wish there were more and tougher opponents. Though instead of towers, you'd use your dwellers (and possibly a few turrets). I also wish there were melee weapons in the game as well as other weapons that went for associated S.P.E.C.A.L. stats.
Also... Where are the Mr. Handy's?
I enjoy the game so far. I just wish there was a more clear purpose or an end game /objective other than just get a big population/economy.