My vote - don't do another NS "fix" where you negatively impact an established toon. Fix the raid and make Traya harder to kill, don't break another well established toon. Sure, it's been ages since zFinn was an effective arena leader, but he's still effective vs the tank (and even more so now 3PO is around, as we all know).
The HSTR mechanics are the problem, not zFinn. Make Traya resist expose and this all goes away.
Second option is to tweak 3PO, as he's the new toon.