This might sound a bit nit-picky, but it's caused us some confusion and extra work:
Archived events don't show up in the CSV export page, but do show up in the dropdown lists under "E-mail Registrants" and "Events" (causing us some temporary confusion). This means that the dropdowns are annoyingly overpopulated and there's absolutely no way to reduce the number since unpublished events also show up in the dropdowns.
It would be nice if archiving an event meant that is disappeared from the dropdown, or there was at least some way of reducing the number of dropdown events (we have lots of repeating events).