As a side note, where the wall's can capture - that is only the side walls - not the top or bottom walls.

The only problem I see with a limit on whites first move is that I think it might be too much and then give black an advantage.

The "swap" idea is pretty good, but at least for me I think it would not work as well for this game.

When I first started playing, all the play was in the "middle" of the board and was fun - and I think making the walls be able to capture would move the game more towards the middle of the board.