An extra 30 lvl will be great scopley .
Since you have no plans to stop 6* promo at least make them worthy.
An extra 15-30 lvl with rings only for 6* (not the S class) that gives an extra 10-25 % in total status will be fair .
Since we all knew S class have an average of 200% status comparing to 6* .
I am sure no one will say no if you do this scopley.
Your last promo Kyle will have a max status like this
Att 2400 def 3800 hp 2400
It’s nothing comparing to S class , but it will help a little bit for both players and the company.
1 - The players will pull again for 6*
2- more lvl means more gears , and you want to sell gears right ?
Just think about it.