I agree! Positivity! Mutual feelings! We're all part of one big family!

But seriously, I think you're right that superusers are the weight behind the whirlpool that spins Hubski. I think a few neat little features would be great to implement:

1) If a user you're following is inactive for X days, you should get an alert of some kind when you visit hubski that prompts you to unfollow them. You should be urged to. 2) If you haven't commented on or shared a user you're following's posts in X days, then you get a prompt to stop following them. Because clearly you don't care about them that much. 2.5) It occurs to me that if someone is inactive you will see both alerts, so I guess I would put something in so you only see the inactive one. 3) Seriously consider the ramifications of having a "follower limit." So only a certain number of people can follow you at once (say, 5% of the site's total users at absolute most). I like this because it will weirdly encourage a lot of things- following people who follow people, more use of the global and chatter pages if you want to follow big users. And I think, very importantly, if this is implemented, then users should have the ability to edit their followers. This way you can cull your following as well as who's following you.

I don't recommend that #3 happen without some modelling and forethought beforehand, but I'm fairly certain it would prevent any serious super-user problems.

I don't know whether or not this already exists, but a Hubski account should also probably have a point at which it's automatically deactivated- has no followers/following, and only the base hub and badges remain of it. I mean, after, say, a year or so of inactivity. Obviously not much of a problem yet.