To be honest I didn't really like the servers with more than 32 players in BF2 or BF2142, it got a bit mental. However most of the maps were really well suited to that number, excluding the absolutely gigantic ones that nobody really liked anyway. Maps like Suez Canal and Gulf of Oman were spacious but pretty much perfect for 32 players. The one in the BC2 beta is clearly too small for 32 players IMO, but then it probably suits the CoD-like gameplay the Rush game mode is targeting.
From what I can see there's more to the map in the BC2 beta, but as in the previous games it's limited as per the game mode.