Here is my ikaris stats at rank 4

First fight is against winter soldier, I used sp2 and heavy attacks to avoid the refresh bug, then built up to max incinerates and used sp3. After that I just repeated the process

Next is the captain marvel fight, where I built to max incinerates and spammed the special 1 refresh. Even accounting for about 30 seconds less fight time (shorter special attacks) the difference in damage output between fights is 10-20%.

Personally I would keep him the way he is, with the single refresh on sp1, from what I can tell, the numbers aren’t really broken.
A maxed out 5 star is about 3 times stronger than the Ikaris I used here, and therefore would have 1/3rd the fight time. That’s a 1 minute and 40 seconds, which is miles behind most DPS.
For reference, that’s about dragon man levels of damage against class neutrality and no buffs.