I was told every edit creates database bloat. Here some drawings.
This is simple image showing how data circulates in OSM:
Why grey revert? Reverting store is cheap. "Version 1 is same as version 3". You keep current version in current data base and just pointer in archive.
Look closer at archive and visible separation:
It is sane way to do servers for OSM. You need not tell contributors not to contribute because of large database. Real users need archive part not.
If disk space is low: buy more! Ask for donations! Here is rough simple list:
I remind OpenStreetMap is easy to donate: http://donate.openstreetmap.org/