Tera(ble) would be perfect if it went F2P because I would expect less from it, its not worthy of a $15 subscription. Adding a thousand "Go kill 10 rats" quests to a grindfest, still makes it a grindfest...
GW2 isn't a game that is going to take away subs, since it doesn't have a fee other than the box purchase, its a great "filler between content patch's" game to play alongside a sub based game.