If you're just looking at Jedi for arena and to run a full squad... yeah, I get your point, pretty much every team can counter them on defense. The, maybe sad, truth is that the in-game Jedi are designed for younger players both in age and maturity in-game. A lot of Jedi tagged toons are used early and then you move on to other factions that are more relevant to current Star Wars themes (e.g., resistance, JTR, etc.)
QGJ did have some arena moments when they released zetas, but that has obviously come and gone. I'd also ask, just because they're you're favorite faction do they really deserve to be the strongest? If we use today's canon as the guide, they were never terribly overpowering. Maul, Dooku, Palpatine, GG, and clones whooped em.
Yes, I know Maul and GG died at the hands of Kenobi... which is probably why both of his characters are great!