- Developer is obliged and expected to release regular content updates and improvements to the game - Do you think WOW will get to where its at now if it has been F2P since beginning?
- More resources for the developer means better chances of getting better support vs poor support
- Developer gets to hire the best talents to develop the game
- Lesser gold farmers that ruins the economy
- Lesser 10 yr old kids who are more likely to troll and grief other players
- Everyone is measured on skill, not the amount they pay for items - you don't want another player being better than you because he spent 10x more than you even if you spent 100x time than that player. If a player pays unrealistic amount of money for items then most players will lose the will to win if they cannot match what that player paid for.
add on to the list!
... and oh yeah, lesser Chuck Norris jokes on chat
as what they say, you get what you pay for.