Well, it is semi-random. Your main abilities will be under your control, and those abilities have more impact on your character than anything else. As for your subs, it is the luck of the draw. Which I find fine, since now people won't be focused on finding the "best loadout" that everyone ends up using. Choose your gear depending on the main ability, and everything else should be the icing on the cake. Think a sub or two you rolled is useless? Reroll. Not only that, but everytime you unlock a new sub ability, a roulette starts spinning, so who knows if there is a way to manipulate it for the right ability?