Note: this used to be lvl 12 or so, this and other changes made the other sub-classes quite playable from early on, whereas in back in alpha the only choice was empyrian and the others were borderline unplayable early on.

You may also add that the aetherwalker has the only useful  unique perk of all 3 sub-classes, and that one can not be accquired later on, which now makes it pretty much mandatory to start as an aetherwalker.

3 points in the hit points tree can get you 25 SR per warp heat point lost, which goes well with the healing from the focus tree.

4 (different) points in the hit points tree get you inocculator reset when at 25% HP which can be a life saver, especially for less experienced players.

5 to 8 points in movement give you a good basic and also situational increase in movement speed, and at least partially alleviate the otherwise unbearably slow default movement speed.