Question for Thief who also play Warrior.
Honestly, if you are looking for a change up never go Melee to another Melee centric class
My second 80 was a Mesmer and I love it. You could also try Elementalist both very important in wvwvw
My first character was a warrior and my second was a thief. The classes do feel distinct from each other. I enjoy playing both of them a great deal. Honestly, the leveling content was more of an issue than the class distinction for leveling my second character.
I did a lot of crafting (3/400) and WvW to level my thief, couldn’t stand repeating a lot of the same content that was still fresh in my brain from leveling my warrior.