I believe several of the most under-utilized classes include Rogues, Wizard, Bards, Paladins, and Warriors. I agree with all previous posters, and there definitely was a min-max vibe earlier in the server's history ("why bother playing your level 3 warrior unless hes already decked out in crafted/mithril?").
That does seem to be changing however, and you are seeing a lot more casual players find their way to the server, so play what you like and dont fret too much over SSOY Envy
[You must be logged in to view images. Log in or Register.] If you do decide to start with a non-farming class, it may not be a bad idea to go the typical route and start in Freeport and hit up EC 50's for buffs. Theres a good amount of content to level on the area as well, so there wont be any need to travel overly much.
I personally prefer Qeynos/BB for my low levels because of the gnoll fangs and memories (that area started it all for me back on Live), so dont even let the EC suggestion limit your options - have fun!