One major thing I think should be implemented is that when you're viewing all of the boards they should be organized by type and DPS, either ascending or descending would be my personal preference.
Also some upgrade system that would apply to all boards of a specific type would be really useful.
A GPS (gold per second) for each individual board, DPS and GPS for each type of board would be great.
Really hope to see a bunch of needed improvements on this game, it's potentially a really great game, either 4/5 or 5/5 stars from me with updates! Otherwise as is, 2/5. Up to you to make a decent game really awesome if you want! :) Thank you either way for a few minutes of mindless fun.