I'm not entirely sure which one is stronger Mage/Mage or Rogue/Rogue I would say that both are pretty much equal. And about competeting for #1, I meant if you're playing comps other than P/M, R/M, R/P you most likely wont be able to get to the top regardless of how good you are. That's the way this bracket works. It's not impossible, but really hard even with double tazik.
But don't take my words to heart. It's been quite long since I actually cared about 70 arena, not ever since my friend quit mid s9. I'm more of a BG person who simply just twinks for 'fun' and to kill time. Eagerly waiting for Tera-Online EU launch.