Not sure if this would clutter anything, but after editing for several months I have been thinking about this idea of allowing editors to write notes with a certain edit.

Today I fixed a user reported problem stating that you could not turn left at a certain red-light, however looking at the aerial it just looked like a normal red-light, but after going into street view you could clearly see a "No left turn" sign hanging from the red-light.

Instead of locking that road segment, it would be nice to put a note that other editors can read that would say "No left turn sign posted."