I didn't get far enough in to check. I'd be surprised if you couldn't, though. Now, in theory, if you put enough time into it, you're suppose to be able to get every skill in the game through just leveling, quests rewards, and sky shards, but then it's about making sure you get all the ones you want for sure.
"Then I'll put it another way. I'm clever, and you are unspeakably stupid!"- Takuan The Official FŽanor fanboy.