Yeah it was like this for warrior vs paladin. The big thing determining that warriors were underpowered was the fact at the time they struggled with the community stragedy of dealing with turn 1 and 4.
It wasn't the fact that players couldn't play the class right because on turn 1 there wasn't much a war could do to survive 3+ stacks infact 3 stacks got a warrior near death. What square intended was for the feeding in turn 1 to countine well to the end of the battle. What players did instead was feed one or 2 slimes before the split and then all feedings stopped afterwards. 2 paladins could handle 3+ with cooldowns and thus the dps lives were made easier while the warriors had to either overgear or get excluded from coil entirely ontop of the dps having to feed slimes to the warriors snake after the split. The consenus is that wars could complete all content and they did it just was too much of a pain in the ass for a lot of statics to bring them so wars got shunned and hence why they got buffed.

That's whats kinda happening to blm at the moment. Sure you can get a blm to do the same damage as the other classes its just less of a pain to tell that blm to switch.