I want to make a list of maps that can have substantially unbalanced starts (that people nonetheless seem to play 1v1). I'll try to give at least one of the variations I consider unbalanced, though in many cases there are multiple ways it can be unbalanced.
List:
-West Illuria (southeast or sw v. ne or nw)
-Illuria (both versions played, though imbalance is greater in darkh's version--south central (in mountains) v. most other starts--especially the two central starts and nw)
-Europe (all of them, including 3--I'm not sure if anyone is even trying to balance for 1v1, but if so, se (Egypt) should not be a possible start, against Rome, France, Spain, or Germany it is terrible)
-Outlands (se and nw can both be bad, but se is probably worse)
-Lands of lore (this map is not really finished and should probably be deleted, sw is terrible, in part because of starting unit restrictions)
-Britain (center starts are vastly superior to edges, especially south)
-Greek Civil War
-Hibbletobs (center is much better than edges, teal start is best and sw or ne should not win against it)
Some of these could be improved fairly easily (by limiting 1v1 starting possibilities). Some of them are just not meant for 1v1 and should be removed from 1v1 ladder game maps. Others would take some thought and changes to the details of the map.