Give free players a 20 or 30 day free trial with all expansions for new accounts.

Enough time for them to experience most areas of the game, especially if told about the game/encouraged to play with current players who can show them around the game and get them hooked.

Could still retain the basic, low access Froob programme although in all honesty I think that only exists in its current state because paid accounts have become overly dependant on them. It certainly doesn't work now to generate more player interest.