Thats if you want to create some sort of a class at all.

If you dont, you can just pick whatever skills you want - as many as you want and play like that. I certainly do and the gameplay is just fine.

Basically, you can play a focused "class" or you can play as any kind of mix of skills jack of all trades. My point being, there is really no reason to limit yourself to some sort of pure class - unless you really want to.