I'd say USA homefront is the best, and this is why:
Pros of USA
-5 Starting Cities
-Variation of sizes of countries, positioning and types
-4 Player coalition
-Set point and population throughout whole map
-Some AIs have two cities
-Navy can either be really useful or not possible
-Land units like railgun actually useful because so much is landlocked
-All resources can be anywhere (aka food in cities), except goods only in cities
-Virtually uniform amount of points and provinces starting off
-Cities on island
Cons of other maps
Europe 22:
-Imbalanced positioning
-Some resources poorly allocated
-Tons of inactives
-Random noncore crimea
Europe 25:
-Resources are very hard to get
-Imbalanced (but realistic) point and resource allocation
-Lazy people make boring coalitions of biggest players
-If all the large players go inactive it's ridiculously hard to move through giant AIs with huge armies
-No starting occupied cores (china can't use the Japanese occupied parts)
Pacific:
-Too easy to win in new update
-Predictable regional coalitions/ game dynamics
-Imbalance in map
-Islands are very bad and virtually useless- less resources, no cities, not refueling as they were historically used for
Arctic:
-Mainly fighting AI
World:
-Very laggy late game
-Takes a long time to finish at end
-Morale and resources become ridiculous unless really smart and careful