Now even Unreal Tournament dev. system want to go this way, free to...well...download...you figure out the rest.
Unreal tournament will be a very interesting case study over the next year or two, because there are a lot of different variables that don't apply to mobile gaming.
First, a few questions regarding the market model:
1.) Will the game be sufficiently open source that you can download the source, write in the MindPrison Content Market, and distribute the recompile? Android technically lets you do this, but short of Amazon, no market has taken hold since Google Play comes on literally every Android phone sold through carriers. Unreal Tournament is not as similarly beholden.
2.) If it's not that free, will it be possible for modders to release their maps independently, and for players to install them without going through the market? Also different from the mobile market since every UT release ever has had this system in place; users only familiar with iOS will be confused but I see the overlap between the two markets as vanishingly small.
Next, a few differences with the TRUE market. F2P games are, ultimately, marketing to players. Unreal Tournament makes money another way: directly through Unreal Engine 4 subscriptions and the gross revenue therefrom. $20/month per subscriber starts to add up when we add in all the modders and map makers. Similarly, the next Gears of War release will make Epic a fortune with that 5% gross revenue thing happening. Epic doesn't need to make a killing from players in order to get their hookers and blow. Unreal Tournament is a tech demo for the engine and a low-barrier-of-entry for indi developers to get started.
Finally, the Epic Games that released Unreal Tournament 3 was pretty awesome. Why? Because despite not selling as many copies of that year's Call of Duty release, the folks over at Epic Games did release five update packs including the Titan pack (which had several modifiers, new gameplay modes, and new maps) for free, a year and a half after its release. It was also the only game I'm aware of that had a full plastic-disc release that never required an internet connection but also let players put their CD key into Steam and get all the wonderfulness of having the game on Steam. You don't see that kind of dedication from Activision and while it's been quite some time, I'd at least like to think that some of those people are still in charge of making decisions here. I'm fully aware that it's an unreasonable amount of optimism to have, but what can I say - I have hope.