Mesmer Guardian Necro or Ranger?
Honestly, if you didn’t like early game mesmer then you may not like later game mesmer. But I do think that level 15 is a little early. I started getting bored of my mesmer around 45 or so. Currently playing Ranger and I’m 36 and already a little bored.
It’s up to you ultimately but my advice is to stick a little while longer.