This actually affects all versions of Confluence I've tried 2.2.9 & 2.3.1

Remove web seems to be an atomic operation. While it is working, all users are locked out of confluence. On a web with 600 pages, (and perhaps 5000 total page revisions in the histories), doing a remove makes the rest of the wiki unavailable for 10-20 minutes. We are doing a series of conversion projects of moving webs from other wikis to confluence, and as we improve the converter, we need to be able to remove previous versions of webs from confluence before we rerun the converter on those webs.

Confluence needs to minimize the amount of time the system is locked down, and do most of the remove on a background thread. It would be ok if a new space could not be created with the same space key until the remove is complete. A status screen would show the progress, and an API call to tell if the system is busy removing spaces, and which spaces it is removing.