[MajinDragon]

I think a better option would be to free up absolutely everything. Any payments would be for fashionable clothes (including decorative armour), other goodies like bonus exp etc; the kinda **** u see with games which have a coin shop. Development would ofcourse have to pick up, more money would be raised and more help from a larger playerbase would come to aid in that.
A problem with your idea is the feeling of opression. It would probably increase the number of visitors, but no one will subscribe for content that is lacking. But those who play with full rights and become a member of the community, may pay for fashion ware, or those added extra's.

Ofcourse these are all assumptions.