On 2) you say "which means you have two weeks of no service at all". Well in Prague, we just use busses when the tram line is being repaired. Its like a downgrade. "Oh, tracks are being worked on, I'll have to take the x6 bus rather than the 6 tram." It sucks, but its far better than using busses all the time ;). And of course, you might think that it is wastefull to have a host of busses just waiting around to be turned into "replacement lines" for metro and tram and other busses that break down, but it is really usefull. And when there is a big event at the convention center at the edge of the city, those busses get used then too. So its not wasteful at all.

3) I know that they have to sweep the tracks, (Modern trams actually have brushes installed in the front) but when you have tram lines with a tram comming through once every two minutes at rush hour, carying thousands of people in a day it hardly seems like a large expense to have an old man in red overalls come in at night sometimes an polish and sweep out the tracks.

4) I know, this sucks. Especially when there is an illegally parked car, forcing you to lane change.