I'd love to see an expanded, upgraded collection, but only if A) it debuts on PC and B) it includes MGS4 and possibly Peace Walker C) all games are upgraded, "best, integral/substance/subsistence style" types.
We've already have plenty of remakes of MGS, re releases of MGS2 and MGS3 etc... another collection that basically does more of the same for consoles, bores me. MGS4 is the only one I've yet to play/finish of the main series; though I eventually got an (original, non-cutdown) PS3, I found that MGS4 was hobbled by the fact that MGS Online was removed, but along with that, there a wide variety of single-player, code-unlockable items that required download, and I recently heard it is no longer possible to acquire them. I can only hope that I was able to collect the full set back when I first got the game.
The PC is by far my platform of choice, and I went out of my way to buy MetalGear Rising: Revengence to show Konami that the platform is viable - that they should bring "best versions" of their titles to PC, with a reasonable price was was done with MGR:R. I'd love to finally play though MGS4:Revival and a version of Peace Walker enhanced for more reasonable controls, on PC. I know Ground Zeroes and The Phantom Pain will finally be coming to PC, and I plan to buy them both, but I'd love to see a collection of the "enhanced, updated whole saga" on PC (especially MGS4) first.