Simple solution for the "Level Paradox".

Level Paradox

Simple Solution

Aftermath

Simply the current situation in Pit People where it's better to pick low lvl fighters into PvE (especially the pit) because Lvl ups restoring health is much much much more game changing than few % dmg increase. If I go Unfair Challenge I pick my lowest lvls. Basicly it punishes you for leveling up someone too much, which is unheard of (with exception of twinking in World of Warcraft haha).I know it's uncommon but make number of experience needed for lvl up same for all lvls. 1-2 and 98-99 will take same number of experience points. It's unusual in anything with levels, but it's needed.Edit: Just realized that Overwatch uses this. So it's not that super duper rare. 1-10 can slowly rise 10-999 will be the same.Make lvls go beyond 99 (with bonus % capped on 99 tho) so people can brag about their lvl 850 someone. It will be another incentive for leveling a character because at the moment there is none. As for the incentive for playing fresh fighters I think that's a great opportunity for daily quests - something like "play with team of units under lvl 50".