So, an unseen skill tree? I think that would be pretty counter-intuitive. One part of the suggestion that I do like is that if you don't pick a skill at a certain level, it can appear again later. Having a random selection of skills to pick from is great, but it bothers me that I can only pick up certain skills at a specific level, especially since the greater part of the game is left with no new abilities to reward advancing the character level. I would love to see a progression system that recycles unpicked abilities from lower levels, so that I have more long-term control over my character builds.
I realize the randomness of the ability selection contributes to strategic challenges and excitement when you get the ability you want, but once you're in the character levels where there are no abilities left to pick from you have already overcome those challenges, and it would be nice to be rewarded for that.