Which class to play?
Im sure others can go into more detail. But if you are looking for a class which is good in all gametypes and will probably remain like that forever then I would suggest ele. They’ve been top in PvE and WvW since the beginning. And in PvP they’ve had multiple phases of being a top tier class.
Also ele is a pretty fun class to play. Easy to start and learn. Hard to master.
Ele was a class I was definitely thinking about, along with Necro. Anything to say about Necros?
Necros have one problem (for someone), they’re lacking in PvE group utility. Otherwise, very interesting and fun class, great for “dark” personalities :-)
Id only recommend necro if you dont care at all about being efficient or useful. Its the bottom tier class in PvE. So if you ever decide you want to speed run or join a proper dungeon guild. Or you just feel like helping the group a lot more. You will probably regret playing the necro.
That said it is pretty fun to play. Its a class i generally only do solo stuff with because i like to contribute as much as possible to the group. And necro doesnt do that but its still got a nice feel when playing.
MM is the closest you wil get to anything similar to Mesmer play style. For the most part, it is completely different. Guardian probably has the play style closest to Necro, if that gives you any idea. Necro is a face-tanking profession and was given the Death Shroud transform to aid in sustain.