I like the idea of staking. My main issues with it
  1. the UX is tricky - it's quite a cognitive load to wager 1000 sats on other people seeing and agreeing with you or waiting for mod to grant you the stack back. This perhaps makes sense as the community gets larger - it's worth risking the sats as you hope to get even more back.
  2. It could deter posting/commenting too much.
Messing with the ranking algorithm could work. HN and reddit do this I'm sure, but given that the source is open, the algorithm would need to account for that; e.g. age of account would easily be gamed, as could post and comment count. Also, most of these other tweaks prioritize seniority effectively, which is why HN IMO is hostile to Bitcoin in the first place. We'd have to be careful to not recreate their problem - 40 and 50 year olds running the site.
BTW, tips don't factor into ranking right now. Just upvotes which are capped at 1 sat/user. Every additional sat is not considered in ranking - they're just tips that go to the user.
Another angle: rank purely by the amount of sats paid to the site for a post. That way it always costs something real to rank higher and it's also straightforward in terms of cognitive load. But everyone other than the OP doesn't really have incentives to put sats into a post - unless those sats somehow get redistributed.
If you or anyone else has more ideas, please share them. I'll tip handsomely for simply more angles to consider.