Knights and Rangers could be made into 1v1 fighting machines. I can still recall the days when knights had to restat into a blade build just to level faster because AoE was too costly and slow. Rangers had it worse than knights because of their lack of HP and defenses, and of their reliability on block to tank.
BillPosters can also be made into an AoE type, since they have like three skills total for AoE (one assist, two BP). It's just slow due to similarities from knights AoEing.