The short answer: nothing.
Seriously though, as a person who likes to try out different games and hates have to cancel and resubscribe every time I jump, games without barriers to entry are awesome. The latest rumble in the Internet is Turbine taking Lord of the Rings Online “free”. As an observer of the MMO market, it isn’t hard to see why they might do this. Some reports claim that Dungeons & Dragons Online experienced a 500% or more growth in revenue with their switch. LotRO has always been a decently performing game, but if the switch gets them more players and more money while also making the game easier to try, well, more power to them.
And before people go off half-cocked calling them money grubbing or greedy, making games costs money. DDO has had several content expansions since they went “free” and that is entirely due to the influx of money. If companies don’t keep an eye on the bottom line, they can’t afford to make new stuff, and without new stuff people quit, which just leads to less new stuff.
To be honest, the only issue I have with the current trend of F2P games is that I feel the term is less and less accurate. Sure, technically all these games are free to play, to a point. But all of them have velvet ropes for subscription and/or item stores and more. A better term, in my opinion, would be to call them “Pay What You Want” or “A La Carte” games. The reason is that, for example, if DDOs 500% revenue growth is true, I doubt it is an even distribution. Some players probably pay less now than they did when it was a subscription game, some pay nothing at all, while other players may be paying ten or twenty times more that the original subscription.
For me, I say, “Bring ’em on!” Games with a low barrier for entry get my time and have a better chance of earning my money. Heck, the game I spent the most on in the last year is Wizard 101 as I play through and buy content as I need it, playing and paying at my own pace. I’ve been playing Puzzle Pirates for years and I’ve never invested a dime into it… but I’ve traded earned cash for bought cash (Pieces of Eight for Doubloons) that someone else had to buy, so my playing has earned them money.
I see nothing but win in this trend… Games that are well designed are worth playing no matter the pricing structure. Games that are blatant cash grabs will (should) have a short life.