I'm gonna address a couple of your points. I addressed your 2nd point in your ClamAV thread.
Your 1st point is valid, we may need to throttle a mailbox archive search so that it does not affect the performance of the rest of the server. However, archiving will be slow by nature, it's why we designed the page to "run in the background" as in searches performed have their results temporarily stored in memory, for a couple hours after finishing.
Your 3rd point is interesting, I'll check our log for those errors as there might be something we can cleanup to fix that.
Your 4th point, When users are Queued for indexing they will idle for a set amount of time before actually starting their Index. When they are Completed we keep them in the list for I think 2 minutes before removal, I can double check this. Your point about it always indexing is a good thing, it's actually doing its job as mail flows in it will have to update the index for your users. ANY change to an email, calendar/task list, contact list, or notes will trigger an index.
@Scarab, I'm sorry you've had a bad experience with support. If you are still experiencing any issues go ahead and DM me and I can work with you directly. To say we don't help is false, support has been working very hard to keep up and as far as development is concerned, we are a bit split atm since we have some working on MAPI and a couple still trying to manage bugs and support work.