Some quick predictions:
Based on the bits we saw on the livestream last Friday, Thief Acrobatics is going to become about regen. Health regen, endurance regen, and initiative regen. While Stealth spec will be about spike avoidance and recovery, Acrobatics will be full on sustain. They were already playing around with this in the last two patches, but it looks like it's going to be where they go for sure after the fact they took away its heavy dodge focus. Daredevil will differentiate itself by providing hard returns for investment and encouraging more active skill usage. Acrobatics will probably still need buffs, (if it could get initiative regen that makes it overall superior to what Trickery provides, it would be best), but I'll use it no matter what.
Warrior Axe was the weapon with the least utility, and it looks like they aren't changing it much. Warrior will get sustain buffs, and they will matter, but Warriors will likely be nowhere near the top tier in PvP. Axe buffs might increase its DPS enough that with Strength + Berserker it has a decent power damage spec for raids, which is great for the overall health of the game, but most people won't care. They still need to do something solid about Fast Hands dependency and it's irritating that while the changes to Rifle help that, but Rifle is still a weapon that benefits from multiple traits in Discipline.
Elementalist and Mesmer may not be bottom tier in PvP but will be treated that way regardless until one of the top teams does decently well in a tournament with one. Mesmer may actually get some other buffs to avoid the stigma, but people will continue to say that Ele is impossible without Healing Power + Toughness + Vitality. I don't enjoy Ele enough to bother proving them wrong.
Speaking of new Amulets, one interesting thing they did by lowering the amount of Toughness and Vitality going around is make the base health and armor values of each of the classes matter much more. This also means that amulet valuations are going to be even more diverse among each of the classes than before.
Necro might grudgingly reach top tier in PvP but everyone will still hate them and most people and teams will shy away from them. Necros were the only effective bullet in the current meta and only Abjured took proper advantage of that throughout the entire PvP League.
Engineer and Guardian will stay about the same. They both have all the tools they need to stay afloat, although they don't have every possible tool the players themselves would want.
Revenant is in an interesting position, and I wish I played the class more. There's a decent chance that the next metagame will revolve around Thief, Necro, and Revenant. They'll likely get knocked down a peg, but they still will likely be everywhere. And they do provide an effective condition build snugly fit in-between the spectrum of Necro to Engineer.
Ranger is the wild card. If nothing major happens to them, they'll end up like Engineer and Guardian. Unlike those two, I feel like the Ranger meta has barely evolved because Druid isn't liked much or something. There are a wild amount of builds I've fought against since Druid inclusion, but nothing standout. It will likely get some tweaks in different places that help further its personal meta.
