Sorry, no experience with mesmers at all past like ... level 5. Lol. Eles do well in melee with D/D, however, so long as you (again) don't try to glass cannon it. You can output solid, consistent damage, and it's by far my favorite playstyle. Don't listen to the people who say it can't be used in WvW, either; it totally can as long as you learn your limits -- which takes practice/trial and error -- and learn when to GTFO, even in larger clashes. It does take might stacking so you don't hit like a wet noodle and a lot of practice and micromanagement, though.
You seem to really like the necro flavor, so that would be my ultimate recommendation. With GW2 you can make any class fit any role you want for the most part, though not in exactly the same way.