I believe that giving us more options to experiment with more classes wold be a great addition for the creative fps player. Having only five different classes limits this creativity, if you say the average player likes to snipe, run and gun, or be stealthy which ends up taking three out of five sets. Some people also like to have an alternate weapon setup for a similar class this leaves you with one class left to be creative.
My solution is to give the players more custom class slots. This could be increased by adding a given extra amount of custom class slots, or my personal idea of having a scroll bar type selection area for having as many classes as someone can develop.
Start debating!