Hi
I’m playing this game for about 1 year now (with a big pause of 8 months 
) and i can’t understand how a feature like that can’t already exist.
The idea is to create bracket in function of 
. If you go in
bracket you could only use
characters. And more you go in a better bracket, bigger will be the rewards.
Exemple:
You are a new player and only have
character you will choose the
bracket and get rewards to up your
and some
to help you in your evolution.
If you go in
bracket, rewards will be
and some
.
If you go in 3
brackets rewards will be
and rare
And
bracket for
characters.
Of course you can add Iso and HP in function of brackets of course.
If you want you can play on several brackets if you think you can be enough competitive to earn more rewards.
Here is 1 idea for stopping this injustice of begginers or occasional players who play again veterans with lv270 team.