First, thank you for being the leader in forum software. I've been using IPB since the beginning, and it's great.
The biggest concern I have is ensuring my database is always available. I have 13+ years worth of forum data, and when performing upgrades, installing hooks, etc, I'm always concerned about corrupting the db. Yes, I have backups, and I've had to restore from backups. Unfortunately restoring from a backup can take several hours.
The biggest feature request I have is ensuring my data is available. Perhaps it's possible to somehow take db snapshots? What if there was a second database that got replicated every night, which would at least provide one good backup daily. You could only go back 1 day, with just a few clicks. I'm not a programmer, however this is just a feature request that I think would be beneficial to many. Not sure how you would design such a system, but certainly would be nice.
Keep up the good work!