The buy different quantities can definitely be added. As for more walls, we will see how it gets later on, originally I had only 30 walls as max, but I think having a limited amount of walls will create different strategies for setting up defenses, especially when new types of enemies are made and enemy moving patterns and AI is improved. There's already been some strategies made on the Discord, even with the current state. Tower range increase when the towers themselves are upgraded with crystals, but I agree more wall stats are needed :)