It won't happen, but I like this...
Hard cap, top and bottom, with each player's contract being a sliding percentage of the total. No MLE, LLE, no exceeding the cap and no going under the bottom cap either. All teams must have X number of players (say 14) under contract at all times.
For example, James signs for 30% of the cap plus 2% increases for 3 years. This year the cap is $60 million...he receives $18 mill, next year the cap is $55 million...he receives 32%x55=$17.6, the following year the cap is $64 million...he receives $21.76. Whoever he signed with must, each year, fit the 15 man roster within 100% of the cap...failure to do so results in contracts being voided and heavy fines being levied.