best class for game completion?

Bishops.

-Very self-sufficient for exploring and questing (Heal, Dispel, Door)
-Tele Mastery is probably the fastest way to complete low level collection/hunting quests
-Actually a great mobber if funded enough, especially post-jump
-Really easy to get parties for PQ's/bosses
-HS for really cheap and lazy exp, you can get to 200 without any effort

+1 for bishop.