New subclass system

During the last year many people posted their ideas regarding subclasses, so here's mine:

I would probably add it at level 50 or so, maybe a little bit earlier in the game, and it would come with a series of quests in different regions according to which subclass you chose.
There could be a different subclass for each region, like norse, atlantis',... each with unique new versions of the old skills, like wolf pack, which can summon crabs or anything, dealing elemental damage, and so on. The quests will be in painful or above mode, with an NPC of the selected subclass helping you, and at the end you unlock the selected branch of the skilltree.

How does it sound?

Imagine your spellweaver, but with a dark magic twist: it can summon undead though its abilities, and despite having some debuffs on base stats it has abilities that can buff attack atk.speed... when he kills mobs or does crit.
Or an Engineer dwarf, which can build defensive and offensive structures to help the group.