You let a conq get two 3 step combos off on you unopposed? Sounds like l2p issue, honestly.
You complain about brute and carnage at same time making it sound like you can get all this stuff together in one spec.
Conq is extremely powerful for sure, especially brute with a high dps 2h.
By the way, OLP displays bugged dmg numbers when your opponent has low hp. I don't know exactly what causes it, but all of my 4k+ non-crit OLP always occur when the opponent has less than 1k HP left. I've had a couple of 8k OLP but always non crit and with the opponent having 200ish hp left.