My personal aversion to F2P comes from personal experience. Once a game goes free it almost immediate drops in quality as resources are poured into the cash shop. Expansions become smaller while still costing the same amount ( that is if they bother with expansions) they often drop those things that make them unique such as the fully separate and voiced class stories from swtor because they claim it's to expensive to produce. Even though voice actors are on contract for several years and the scripts for those years have already been written (information from swtor's former lead writer).
Also with P2P companies actually have a budget for a month ahead because they know just how many people are playing and can project next month's sub money with far more accuracy, meaning they can now budget for future production/improvements.
Free games don't have this option they don't know how much money they will receive each month as players either buy nothing from the store or perhaps the next month many players suddenly spend several hundred each. Meanwhile those that are avoiding the store are sucking up resources and not playing for the usage. This causes the company to abandon content or lower quality of the content while putting things on the store to lure in more money. This cycle repeats until people stop buying then they put the game in "maintenance mode" so they can throw out the next piece of F2P cr@p.