Frankly, while that system was alright in the past. I honestly think they should do something more streamlined and less restrictive.
Unlock Masteries at level 5. This is when you can PvP and they'll be important. Get all of your points, so you can practice and experiment as you level up.
Unlock your first Rune page at level 10, and a second and third at 20 and 30. This replaces unlocking the Quintessence slots, as the rune page itself allow you to put runes in at any level once unlocked.
And while we're at it, we should get the Rune system improved. Instead of having tiers of runes, why not have the runes strength scale to the level of your account?