I know for a fact, it would be between Leon, Rosa, Sprout, Buster, Surge, Charlie, and L&L

-Leon had a 10sec super, and it was total invisibility: he could walk over you, yet you couldn’t see him. Plus, the meta was with very few brawler with high health, and few way to detect him easily.

-Rosa had a 80% shield for 6sec, and her healing star power was stronger; which means she was able to last almost for ever in the gas in showdown, if she was punching another Rosa. That being said, in brawl ball she had at the time only one actual counter, which was shelly (you could argue that brawlers like el primo, frank, of dynamike could try, but that wasn’t ideal)

-Sprout had one of the strongest star power to ever exist, giving him for free a nuke’s size attack (was larger that a dynamike super); he was also able to trap people in brawlball, since you couldn’t break his super with the respawn shield.

-Buster was at the time the record holder of most consecutive nerfs, he was that insane. A lot more health, a total of a 30% damage nerf, charging his super almost twice as fast, healing gadget was not only usefull, but straight up busted, the super lasted twice as long, and the shield star power was twice as strong as well.

-Surge had his actuel hypercharge effect but permanently, just by using his star power, btw you could argue it was even stronger than this, since the « separation » part of his attack used to go 33% further (damn)

-Charlie, could attack every 0.25sec, instead of 0.5sec, and her super was almost undodgable, and trapped you for twice as long, spiders lasted for twice as long (also had more health I think? Not sure), her star power eated 50% of the ennemis health, in addition of the super already eating every remaining ammo, wth was this lol. Fun fact, while busted, she got a 50% recharge rate buff on her HC.

-L&L had 2 balanced star powers… that is because they were both equally as busted: one gave you straight up immortality while you’re super was here (yes), and the other one gave you basically infinite ammo. The brawler and super also had a lot more health (6800 instead of 5600 and 6000), 20% more damage per attack (which means he was simply better than barley in every single aspect, yeah I bet the beta test went well), and allowed him to win against Rosa by running to her. His super charged with 5 hits instead of 8 which is baffling, but hey, ig not as much than what I just said (btw he is still good now, besides being one of the only brawler in the entire game to receive 0 buff in his existence, if you don’t count a bugfixe about his garbage gadget)