Others have already said it.... but I never want to be playing a game where I can't pay a monthly subscription to have access to EVERYTHING made for the game.
I don't even want cosmetic skins to be in a cash shop... because then the development team has to limit the number of cool-looking items in the game in order to push people toward the shop. This is the case in Guild Wars 2, and it's utterly maddening. I don't want to buy a flaming sword from the cash shop... I want to rip it from the hands of a boss, or find it inside a chest in a dungeon.
And no, I don't want to buy the key to that dungeon chest from a cash shop, either.
When you have a cash shop, the quality of the game suffers, period. There are better and worse ways to implement a cash shop, but it simply cannot be done, at all, without causing a detriment to the rest of the game.
I am very happy that SE has been very adamant about ARR being P2P. I want nothing more than a dev team that is focused on content, and not how to best monetize a cash shop. I want content introduced into the game because it's epic and compelling, and not because certain elements of the content could be monetized in the cash shop.
I've never seen anyone who favors F2P explain why, as a gamer, he or she thinks that would be beneficial. The argument is usually whether the gaming company (SE) will make more or less money. But as gamers, we should never wish for F2P to happen! Other than saving $12-$14/month, there are no benefits that F2P games can offer gamers.