There is a growing sign and welcoming trend that video gaming developers(who are having their games in Playstation, X-Box, Nintendo etc.) are moving into the direction of having their past, present and future games converting or incorporating into online games as well. Since the recent and easy accessibility of internet connection in all continents(example Europe, North America, Asia, South East Asia, Middle East etc.), there is a huge demand from the vast world population of online gamers and multi-billion business for gaming developers of all types.  

 I'm a perfectionist and never liked to settle for second best... which is why I main in World of Warcraft. I'd rather pay a fixed amount every month and in return get an extremely well polished game with top of the line customer service. It really shocked me when I started in WoW and ever since then almost every other game apparently pales in comparison. Not to say that every other game is bad but... customer support without even having to log out and the privilege of speaking live with a GM... now THATS what I call service.

Imagine a 3rd person platformer/action adventure, like how a modern mario or legend of zelda game plays except theres tons of other people to play with.  That would be pretty cool

I too would like to see more experimentation in this area. I think RPGs fit F2P so well because they are gear and character development based. You just fill your item shop with gear and XP buffs and there ya go. Other types of games may have to think a little harder as far as how are they going to make money off of the deal.

Little Big Planet is a good example of a side-scrolling platformer that has integrated microtrans into their game (costumes, level building items, etc). I think games like Little Big Planet and this new Modnation Racers (seen at E3) have touched on a good idea. Let the players create content. I think if you provide ways for players to make content (levels,dungeons, etc) you can then sell them items, etc to use while creating. This way the company makes money through sales and the players are creating better content out there since their toolbox can grow. And other players get to enjoy the end products as the levels are shared. Win win win.

F2P can work in other genres. Dynasty Warriors Online proved this when they went F2P and used the item mall to provide extra weapon racks and accessory options. the problem is that they aren't many other games that are used online. those companies will never change their business model until something greatly affects them but chances are that won't happen.