I find the selection for arena to be really bizarre. The other day trump got 6? rare draws in a row, up front, and more rare+ later. I get 3 non common cards on average. My 8 win was with a druid basic+2 blue deck, which only beat people who received worse cards than me. And lost only to people who received multiples of purple and legendary and rare. Not "or" they got multiples for all of the above. Very rarely do I or my opponent outplay each other. It feels like an arena in the sense of Roman gladiator entertainment. Will you get full body armor and a shield? Will your opponent be a naked half-dead slave with one arm missing?
I'd love it if they added real Sealed deck competition. Or at least min-max on uncommon draw.