I've noticed today that the Expansion Manager doesn't handle internet dropouts during a download very gracefully..
My internet (ADSL2+) is generally pretty good, but when the weather is bad, it gets lots of dropouts.. takes the modem anywhere from a few seconds to 2 minutes (or more) to re-establish a connection to the ISP. And dropouts can happen every 10-20 seconds if things are bad.. which can be absolute hell when downloading from sites that don't support resumable downloads.
(My best guess is that moisture is getting into the lines/equipment somewhere between me and the exchange.. after a couple of dry days, things improve.. although sometimes it can happen even after weeks of good weather.)
I've noticed that Oolite seems to be pretty good about small disconnects, but if the connection doesn't get re-established within 15-20 seconds, the download just hangs. If there's no progress for 1-2 minutes, I have to cancel and restart the download again to get things going again, even though the modem has already re-established the connection.
If Oolite and the wiki repository don't/can't be made to support resumable downloads, then it may be necessary to have some kind of time-out instituted, so that Oolite doesn't just hang, waiting forever for the download to complete.