minimal marginal excitement
I wouldn't be against a bonus game if it wasn't designed to eat a full 20-30 minutes of airtime and removed the "competitive" part of "TV's most competitive game." Also, having the number of required spins decrease in each bonus leg feels less interesting than the other way around.
I don't know if you could fit a third full round or some sort of additional catch-up mechanism, but what they look to be doing seems a little too simple.