As a longtime follower of Halo there is no place I would rather see the franchise go than sharing releases with PC. It's been a dream of mine for several years now as Halo is the last console exclusive series I actively follow with vigor, despite long-since migrating to PC due to the open nature and decidedly more intuitive control interfaces. The simple fact of the matter is that there are few games (dare I say none?) on any platform with the charm and creative flair of the Halo series. The by and large flawless multiplayer combined with a depth of setting and lore seldom seen in video games makes for an experience unlike any other. Incidentally, the fact that the original PC halo games have thrived with active communities for ten years now is a testament to the dedicated following on this platform. This considered, it is most puzzling as to why Microsoft, Bungie and now 343 have consistently ignored this part of their fanbase.
By now, concerns of piracy should be largely dispelled due to the rise of Valve's Steam retailer and similar digital distributors. A sales issue is therefore unlikely, especially considering Microsoft's positive results from their relatively recent steam re-releases of Fable 3 and Age of Empires 3, the latter of which I purchased myself. A concern in console sales and live subscriptions is similarly unlikely, due to the subjective tastes of a vast majority of the existing fanbase who would prefer to play on console (the platform-relative sales of competing franchises such as Modern Warfare is a prime example of this.)
Though I am as of yet undecided regarding halo 4, pending further information, a PC version would be a purchase made with utmost enthusiasm. As of this point Frank O'Connor has established himself as a worthy inheritor of the franchise creative direction and I largely trust his judgement. I would however like to hear a statement detailing his, or perhaps, Microsoft's logic for keeping halo a console exclusive series or perhaps possible plans for the future in this regard.