monkeydelarge: I am sure he meant "done right" for the gamer. :) And when a game is done right for the gamer, it attracts more gamers. A game designed to make maximum profit is not going to attract a lot of people. And without a lot of people playing, I highly doubt that game designed to make maximum profit is going to make a lot of money. Being too greedy can sometimes back fire on you.
I guess you could try to look it the other way around: which kind of F2P games are the most profitable?
I see "Clash of Clans" and "Candy Crush Saga" being mentioned a lot, so they probably qualify (Clash of Clans made its Finnish makers filthy rich, and more money seems to be coming their way every hour). I've never played Clash of Clans so I don't know how feasible it is to keep playing it without paying a dime, but I know one 8 year old boy who is apparently playing it a lot, and had gotten his dad to pay for the microtransactions. No idea what he has bought there, and for how much.
Candy Crush Saga, which my wife is playing, doesn't outright demand you to spend money, but it is one of those games that try to make it feel more irritating if you don't pay. Like having to wait x minutes or hours after game over, before you can play again... unless you pay.
The game is also designed so that it is more about luck than skill, so everyone will end up failing more and more they progress in the game, and hence every freeloader will end up waiting a lot to play the game again.
The game also incorporates social features where you are competing with your Facebook buddies who is further away in the game, which also pushes you to pay to skip waiting, just so that you can proceed faster in the game than your friends. "Pay to win", in case you care how good you are doing in the game compared to others.
From publisher's point of view, I guess those two games made it right, as they produce maximum profit.