Those numbers on rookie contracts are way too high (10% of your cap for a rookie?), and the minimum is too low (1%=$940k, which is way lower than the current vet minimum). Plus cap holds only make sense in regards to Bird rights and going over the cap, so they wouldn't be necessary in a herd-capped system)
The main issue I see with a hard cap (especially with a rookie scale) is what you would do if a team is at (or near) to hard cap, and gets a top pick. Are they allowed to go over the cap, or are they forced to trade someone to avoid going over? Cutting a player wouldn't help, since their salary still counts against the cap (and if cutting the player didn't still count against the cap, it would essentially mean unguaranteed contracts, which the NBAPA would never agree to)
Any plan which changes the basic structure of the salary cap (or the draft, looking at you, Draft Wheel) is never going to happen without some proof of concept, and that's not reasonably available. The best plan to "fix" these sort of situations is to remove max contracts, but that has its own issues as far as mid-tier players and stars taking pay cuts goes