Given the potential for Luke to finally be in the game, and with what heroes we have in the game at this time, I believe we have the real possibility to actually break arena and have the first perfect team. Please note I do not think arena has ever been truly fully broken where there was one perfect team that was unbeatable at a 60% rate or higher. Even Poe had counters, but they were very uncommon.
Let's assume Luke is released and let's also project the following:
1. He has a tremendous leader skill (cause why not it's Luke) that covers at least Jedi and Rebels and is considered among the best leaders in the game if not the best
2. He has great ability generally as a character (again, Luke)
3. He has buddy synergy with R2 (maybe the lowest chance of these 3, but possible)
Given those assumptions, what comp is going to stand a chance against the following team:
Luke (L) buffing rebels and Jedi with great leaer skill and bringing a nasty overall kit with Chaze-like synergy with R2
R2Z2 - pushing out sizable health and offense to rebels and Jedi
Chaze - what perfect team wouldn't involve Chaze right?
GK - Mr. do it all - elite arena stud - 2nd highest usage on GG
What's beating that theoretical comp aside from a mirror team or a team that also features that same core of heroes?