Is WoL the only one able to master/handle all the classes at once?

[radhaz]

Into a nearby phone booth!

I did notice that npcs are very capable of handling soulstones and developing talent toward a specific class, but are "average joes" able to handle multiple classes like WoL?
Also is there like a lore explanation to how WoL swaps class and gears instantly? Cause I hope WoL isn't stripping naked in the middle of a street then changing into different gears