necro.
dru can solo quite well on bad gear, but they cant sustain the spell output(no mana regen). If you go afk alot then no problem. Personally i dropped my dru at 40, as it was such grind to play.
shm are very flexible solo class, but are more fun with decent gear. otherwise 40-50 will drag on.
any fool can lvl a necro, and sustain it with guard kills.