A lot of other MMOs have HAD to become FTP in order to survive. Some have started off as FTP based on what they learned from other previously PTP MMOs that went FTP with great success ( DDO for example ).

WoW is in a unique position to be able to still charge a sub fee AND offer some of these store items, without a "need" to be FTP. I think its a great idea. How many of us have made multiple new RaF account for the simple purpose of having accelerated exp? I know i have spent hundreds doing it. And i will gladly pay for exp potions and a monthly fee. I do it in so called FTP games all the time. I go gold ( becoming a PTP account ) and also always buy tons of shit in the in game stores for real money.