OP literally means achieving victory with less work. Zem, Taru, Cara, etc, all fall into this. If they weren't OP, people wouldn't be into 50 with O+1/5star ones. Try staying competitive with a 5 star tank like elric or drago on a 44k team, see if you can beat a maxed out 55k+ team. You can't, but you can with Zem.
This is why most balanced shooters limit rocket or grenade launchers, because then it devoids any sense of balance when you can achieve a top score playing one handed. Example:
In Metal Gear Online (2), the game lasted 4 years, the 3 year survival lobbies were filled with 2000+ people in 3 regions each night it was available. Bodies had I-frames to encourage headshots, auto aim could be counter, you couldn't spray against top players, and the nade launcher required like 6 + kills to buy.
In mgo3, you can spray and strafe all day with AA, HS take 2+ hits to kill, while no i-frames on bodies take 5/6. You also can spawn with grenade launchers with no drawback. Survival, now after a year averages 0 to 3 people, despite no region lock, fell to under 300 the 1st month. Mgo2 has a player created 'revival' server that requires a jail broken ps3, which costs mad money, yet usually always has more players on than survival.
That's what "op" crap does, people left after the first week when for 3+ years they eagerly waited for mgo3. This OP crap caters to casuals who don't care and alienates the loyal competitive crowd. Oh, in mgo3, you can get a 1/3 of a kill point for looking at people. People said "oh well it has a counter", yea, looking back and hiding 10 minutes for a 50 to 0 score victory.
Also, just because someone sees something as OP doesn't mean he sucks, it also doesn't mean it's fun to adapt.
I'm considered the best Sniper, I hate sniping. But I'll be damned if I lose because some scrub thought he could look at me, never move up, the nubtube/AA behind a corner if I moved up. See? Not fun. Nor is making great teams in SH and having trouble with underleveled hunters because the game gave out 3 of them for free and placed them in the easiest to redeem shop.
On topic, is Malrath a surefire counter? As of now, he isn't widely available.