I think they could do a taxed floor under the current system. Say the floor is 50% of the CBT. Teams less than $20 million under pay a tax. Teams $20-$40 million under pay a higher tax rate. Etc.
That is actually something the owners in the middle would join with the large market owners on. They are annoyed at the A's clearing a $60+ million profit by not spending any money.
This would not raise salaries enough to change anything at the top. It would just mean that the middle class would extend a bit further.