I think fixing content related to leveling should be top priority.
PvP is nice but it's not crucial that it be fixed immediately. Currently the main quest line in the game is broken, preventing players from reaching over level 57.
There's different departments that do different thing. Fixing (or should I say, unbreaking) the arenas isn't going to have any effect on how long the main questline is broken.
Arenas were fine enough the way they were, then changes came in to make them terrible. Autoclosing matches and making people immune for 25 seconds after dying were things that they just decided to throw in. And those changes are the direct cause for killing 3v3 6v6 and so on. As a result fewer people even bother trying to sign up, which leads to more match closing because of the 80% requirement (that has no reason to be there) is in effect.
I would like to see them fix the pvp reward system.
Honor points for seems materials is decent, but the 1.3 billion for the set of gear, that appears to be level 50, 55, or 60(?), is worst than the badge of the trial/guild title system. The required amount to get the gear is ridiculously high and the gear seems not very spectacular in comparison(or even equivelent) to what same level gear drops from instances, or the gear reward packages(the 50, 55, 60 blue gear packages). Its too high an amount of work for very low rewards.
I think those points are from something else, not the same as honor pts from siege/arena.
But yeah, the pvp arenas suck now.