I'm halfway decent arena player. For the past 6 months or so I average really good. Not going to pump my own tires here so I'll leave it at this. I've played almost exclusively Arena for more than 2 years now. Every mont I play Wild enough to keep me in the good rankings but nothing more. For me it's Arena Arena Arena. I've been around for expansions and new cards for a long time. Now it seems like this new card expansion is really making strides. I've played only 4 Arena runs so far so this is subject to change due to small sample size, but my biggest strength seems to have lost it's power. I'm good at drafting decks and I just can't seem to be able to draft a competitive Arena deck.
Of course this will ease out, but usually I've been able to "feast" with the weaklings after every new card expansion. Now it seems like I'm no longer able.
I'm also primarily an arena player. I played one last night as my first of the expansion, and ended up with a 64-point (Heartharena) Priest deck (horrible, horrible deck). Not a great first impression of the new arena for me, though I escaped with two hard-fought wins.
And while I do use Heartharena, I'm at the point where I barely need it for the draft, I just really like the deck tracker.