drag-select for walls and base builder mode
Walls and base reorganization right now is tedious and time-consuming. I think it'd be a great idea for the next update to incorporate a drag-select type of system for walls for upgrading and/or reorganization. This would be advantageous to keeping 5 x 5 walls in-tact when moving around defenses and reorganizing your base.
Another idea is to have a base builder mode, where a user can rearrange their base without affecting the layout they currently have. Perhaps they could also allow you to keep 2 or 3 different layouts, so you can switch back and forth as you see fit. It is painful to have to exit the game while you are still rearranging your base, leaving everything spread out and open to attack...