Rage skills levelling - how does it work?

[Karlos]

Ok I have now finished the game and I have to say, in the second half of the game Rage levelling is excruciatingly slow. From the point I gained Loki's lava skill until the end I got to level up my Rage maybe three times? That's just ridiculous. Yes, Riftlands comes late in the game but we're still talking about lots and lots of fights. My only fully developed skills were the Vortex, the Gift, the fire arrows and the lightning. That's it. A good half of the skills were only partially developed or not at all.

Maybe my memory is failing me again but I think in AP it was much more even throughout the game and most of my skills were fully levelled up by the last lizard island.