For me, Dust and Pirates are the ideal maps in solo. Aside from being aesthetically pleasing (unlike most maps), they have the right proportion of land and void that makes them enjoyable for a fast paced player, without excessive bridging needed that often leads to void chokes. They also have a lot of open space for fights which is perfect for 1.9+ combat. In my opinion, the layout of these two should be used as a standard when adding new maps in the future. On the other hand we have garbage maps like TNT, Tron, Flowers, the Nether and a few others that don't offer much space for combat, have too many hard-to-get-to locations, too much void or bad design as a whole (It looks as if some of them were built in 2013 by amateur builders).