You can argue about a SLIGHT evelution combined with specializations and reflecting experience...but the actual way of power progression through gear mostly (or linear AA) is not the best idea for pvp, definitely.
A steady progression curve with less high steps would be a LOT better (if you think you should have such a thing). But then you have to disengage pve from pvp, because in pve such a progression actually makes sense under the circumstances.
For opening a levelled field, like on TL or in the unchained mini idea, you would not have to disengage to make them work.
Since they didn't comment on the disengagement (at least i have not read anything AND it would include a lot of database work), can't seem to balance even the same tiers classwise (flawed budgeting) and find making an even playfield "complicated" (actual letter), i would not have high hopes.
About unchained again:
If you can not temporary adjust AAs or give gear, why not simply DISABLE it in the arena? Gearwise you could have a seperate "arena" gear tab, that is customizeable with predefined gear from an arena vendor or from vanity gear or special crafted items. Normal pve or pvp items would not "fit" in there (you alrady have this code in weapon switching and vanity tab to some extend).
This way you would have an easier time levelling the field while still keeping some options of adding more variety or special gear for special rulesets and arenas or offering such a slow progression curve for "arena" battles at least.