I agree with this wholeheartedly. Halo has potential to have a HUGE community again on PC, and its really what the PC needs right now, a popular arena(ish) shooter with plenty of potential to fun custom game types. I know I'm one of many people who absolutely loved the first two halo games but hated having to play the newer games at a friends house because they were only available for a console I have no interest in whatsoever.
Halo's fanbase is already established on PC, they want to give you their money for a new halo game. TAKE THEIR MONEY. I am 100% positive that a well done PC port would be way more than profitable. (and yes, I am aware that porting a game is REALLY expensive, and takes quite a bit of development time.) There are already two Halo games that have proven that. I know that the recent halo games were not ported to PC probably at Microsoft's insistence, but if there's one thing I know about MS, its that they, like all companies, like money. Ladies and Gentlemen, there are few more surefire moneymakers than a PC version of halo 4.
Hell, I'll take a Halo 3 port at this point, that game was fantastic.
You don't even have to port it, outsource it to Gearbox like Bungie did with the first Halo. Gearbox did an amazing job with that port, hell they even improved it far beyond the console version.
