I don't think the index is as bad as it sounds. Without a good index a process has to lock the whole table (on a table scan) instead of taking a more granular lock. On an insert not all the records need to be re-indexed, (I think just those in the page). But if we are talking about an operational database being heavily queried from end users, then a data warehouse database could be in order where, say, one day old data is acceptable.