The grind to 5.5k GS is not so bad. It is roughly 2 months of arena farming plus winning the daily Random Battleground everyday. I did this on multiple alts. If you have full Relentless, Wrathful offset pieces, and the Battered Hilt weapon plus some vendor trinkets, you will be at around 5.6k GS, which is roughly on par with Blackrock starter gear. Beyond that, Blackrock player must donate or reach certain ratings to obtain better weapon and items, whereas players on realms with access to PVE content can grind their way to a lot of ilvl 264+ weapons and gear. I am not convinced that Blackrock players have any lasting advantages over players from PVE realms, at least in the context of the arena. In fact, I think it is easier to argue the exact opposite.