I would say that considering it normal that the partition storing the indexes would routinely fill up and require deleting all indexes is wrong.
I appreciate that being in a position where the indexes are corrupt is not good but then there may be unavoidable reasons why they become out of sync or corrupt.
If we add a new pop/imap server to the cluster is it to be expected that we'll have the service down for 5 or 6 hours while the new server creates indexes and chews through 100mbit of network capacity in the process?
If this is all perfectly normal, I'd rather have a separate index building script that I can run on the file server and then export the built indexes to each of the pop servers to get things running again. I'm guessing indexes for 80Gb of mail could be built on a local file system in 30 to 60 mins rather than 6+ hours over a network?
John