this feature could be added with a level down button next to the level up button at 50% ISO return rate. It could help players make power changes in their roster as needed and add more customization to the game. I personally made the mistake of leveling blade too high-140- which negates OBWs espionage ability and makes the difficulty in PvE very hard for my current roster. I now wish I hadn’t leveled him so high. a level down button would be pretty handy in this situation.
I totally agree. I don’t even care about the ISO. I would actually be willing to spend ISO to lower a character’s level. I made the mistake of levelling my first 3 
that was over 94. Now he is the only character i have over 94 and can only be used for 1-2 matches.
I hope the developers will take this into consideration.
It would help players adjust which characters they want to tank as well.