Having been having a good play around with both the stable version and the beta there are 2 things I'd love to see:
1- staff not being able to access anything until they clock-in for the shift with their passcode instead of entering it everytime they use the till and then they are automatically clocked out on cash-close if not already done manually
2- The ability for admin to arrange the product buttons on the sales screen similar to the way with tables- the system is currently grouping them in a very awkward way and a set grid to move them around on would make it easier to use for customer-facing staff.