I find this idea of trying to maintain a certain "elite" quality quite silly. This sort of growth is a natural phenomenon that happens to valuable sites like HN.

Trying to prevent growth in a certain area (i.e. the less awesome people who you like here) will prevent growth in all areas—e.g. HN buttons could also promote HN to great but new hackers. If you stop these guys from getting involved, you'll cut off the lifeblood of a community whose participants are moving very quickly past the phase where they're excited to be involved in such a community—people get successful, busy, jaded, etc. and not forever passionate enough to bother doing the things that HN needs: reading, commenting, voting. You need new guys to replace the old guys, and both can learn from each other.

If HN is locked down to a degree that its natural growth is stunted, it will die, and probably deservedly so.