It would be nice to have a "buy more" option for when you're building things like walls so you don't have to keep going back to the market to buy it. Also, I just wanted to add that I'm currently playing two other games in this genre from your competitors (hint: SS and SWC) and this one is starting to become my favorite...I love the animations and just the overall look of the game!
It's great to hear you're enjoying the game so thanks for the feedback. In relation to your question we thought this would only be a real problem for the walls, and we include a 'keep adding until cancelled' option on those. What other buildings are you having this problem with?