I really like point 3. Certain achievements should unlock special cosmetic items for your avatar or perhaps a title above the person's username, similar to wow. Microsoft toyed with the idea of awards in the form of special shirts, hats... Whatever for the 360 but hasn't done the same for the xbox one.
Some games should also give more points for difficulty. Basically everyone is online with these systems, whether behind the pay wall or not, achievements could still be tracked. Scaled achievements based on percentage of people who own a specific game vs certain unlocked achievements could help. It would be hard to do on an already established system like xbox live or psn. Imagine the outcry from people loosing points? Nintendo has an advantage here.
