Guardian/Warrior
Both are in a good position in all game modes. Play Guard for a bit more defensive support, War or offensive support.
Recent discussion with varying points-of-view. Might help.
Gone to Reddit.
From a PvE PoV:
Start with Warrior.
Once you know the content, you can go Guardian. You should switch skills/traits according to the encounter, so you have to know what you are dealing with.
Your job as a Warrior is a lot easier. Bring banners.
(ofc there is a lot more to being a good Warrior, I just mean that it is a lot easier to pick up)
Hello darkness, my old friend.