Guild Wars 2

Hello everyone,
I return (when my problem will be solved because impossible to launch the game ^^) on GW2.
I stopped before the extension.

To tell the truth, I hesitate a lot between the Necro and the Thief, to know which class to continue in Main.
I own at level 80: Elem, thief, guard, Necro and Mesmer.
My Main for a very long time is the Thief.
I’m lost with all the change, like the elite special. But also this new way of building.
I have a lot of questions. ^^
Already my orientation is mainly PvE (Raid, Fractal) and WvW.

If I decide to continue the Thief, I hear quite a lot on the external forum that the thief does not bring much to the team, therefore it is not chosen in Raid / Fractale.
This new elite spec, the Daredevil, is a special DPS? The gameplay and the style I like a lot (according to the videos etc.), but compared to a double dagger, what more does it bring? (My question is serious, it seems “stupid”, but my lack of experience since my stop, makes me wonder ^^).

If I play Daredevil, could I play it in several modes? PvE (Fractal / Raid), WvW? Would I be effective?

A very big thank you to you who read me and also to those who will take the time to explain.