The problem is every map has an easier side or map advantage, whatever you want to call it and people know it and join the easy side.(Not Everyone) However teamwork can win sometimes on the harder side the majority times they will lose. Can you maybe change the team join policy where people cant switch to the winning side mid game. Also not let 4 people join one side of a map and 1 on the other, force a even distribution. Example : the map changes to italy,, 4 ppl join t and 1 join ct, force it 1 then 1 or they can spectate. Ptb should not keep the number of players the same either. if terrorist can win with just 8 t's and cts have 14 then so be it because its not always quantity but quality. Switch the bottom guys for teams. Switch the bottom t to ct so its now 7 vs 15 until it becomes even.
Just some ideas thrown out from being on other servers.
dEL