The counter you're supposed to use is a different character.
Public dueling was vastly more fun than GM ft5.
I did a lot of GM ft5 and while it's fun to contest against a single person, the flux of dueling random people you don't know in a situation that leads to conflict or even friendship, GM at first, then maybe BM later on. You want to sorb stack my blizz sorc? I'll load my smiter in the same game. You wanna nk my friend? I'll force you to sit in town until you leave.
1v1 isn't even all that fun to begin with. It's okay, with gm rulesets but 4s and fpk are the true test of skill in this game.
Also, it's stupid and unfun to play with people who nk/sorb and I having to switch to an entirely different character to play just to counter pick that particular person is boring too... If you guys just just gm rules and the sorb was in gm limits to begin with, this entire scenario wouldn't exist and what you're describing wouldn't happen either.
And if you're gonna bm duel don't half ass it, load up trigs and use a mercdin and then you can have a pissing contest that'll last 10 mins.