Hey and welcome back to the game!
Speaking in terms of PvE DPS, every class is balanced except for Engineer and Scout, being on the lower side. Everything else does really good numbers.
I'd say drop Psi and Mage because they bring no utlity.
priest, Druids and Summoner bring awesome off heals and Purifications. The Demo right now is the strongest DPS in AOE, but a 50% nerf is on its way so it's no longer feasable.
Warrior, Demo, Scout and Paladin bring taunts for sketchy situations. Paladin on top of all that brings a Shield and FULL heal for allies, none of the other tanks do that.
Rather something supportive?
Then it's Bard or Engineer.
I did mention Engineer isn't as good for DPS but it beats the Bard when it comes to supporting. double mass puri, shield against demons aoe in mazes.
The Bard however, being slightly weaker on terms of supporting, brings good numbers when swapping to DPS, so it's more versatile that way.
Prefer to heal endgame?
Summoner, Priest and Druid are your choices. All are excellent on DPS roles.
The Priest brings slightly less healing, but has shield mechanics that make up for it, and is better in 2 situations I can think of already, Fenia Cloister 2nd boss and mazes (again, demon aoe's).
It's also the tankiest healer for PvP, followed by Druid.
The Druid healer excels in aoe healing and brings a mass puri too, which the other healers don't. Druid is also going to be able to support in the future, so that's an interesting view.
Summoner is the strongest single target healer with a lot of passive aoe healing, but is the squishiest for PvP. However with skill, you can make yourself a tricky target with Dark Veils and the extra movement speed that the other 2 healers do not have.
Rather play a tank?
Warrior is as it's always been so far, a no brainer. Excellent mitigations and no need to pay attention to certain conditions.
The paladin right now is also an excellent choice, but a nerf is coming that'll the gameplay of the paladin, and make it weaker than it already is.
The Demonologist is also a good tank, but has lost some good utlity with 14.0, shoving warrior and paladin forward.
The paladin has also the top dps right now of all tanks.
Scout tank is something you don't see around lately, but I think it can be good too. I just didn't get to test it enough yet.
The question to ask what is OP is the wrong question to ask imo.
Every class has its own role in the game and brings its own toolkit.