I was thinking this as well, but I will be patient, reserve judgment for now, and allow the prequel to do the build up. To go from being in the Namond/Tariq template to a wise cracking Jason Vorhees, son and cousin killing, smothering old women with Jesus stitched pillows, is a tall order.
To become what he was in Power, He and Jukebox would have to have front row seats and witness the most brutal type of torture and killing of his mother, uncles, and crew. Kanan constant alludes to Jukebox being just as wild as he is.