(From a pure PvE perspective) At this point, it's tough to say. All classes will definitely still be viable in open world/dungeons/fractals. From the looks of things, the same can be said for raiding, maybe even moreso than before.

I think the only 2 classes that will drastically shift in the PvE meta are Engi and Elementalist.

My pick for the new FOTM class is probably Engi. It already had crazy condi DPS if you can handle it's obscene rotation, and they buffed it even more. It'll be super super strong this patch for sure.

Ele got huge nerfs, and it needed it. In my opinion, ele is finally on the level of most other classes. It still has some great utility for certain raidbosses, but isn't the supreme overlord of DPS anymore. And it'll still be fine in non-raid PvE.

Quick note about Thief. It may see a little more love from raiders thanks to the venom share change. It can take Basilisk Venom to rip through breaker bars and not have to sacrifice a trait for it. It saw a slight nerf on staff auto DPS, but I think it'll be fine. And thief will still tear through non-raid content like it always has.