The right service goes a long way actually.
Plus many of the people asking for a PC version probably already have it on a console, they'd just prefer a PC version for obvious reasons.
While the right service might go a long way, the wrong service hardly makes "screw the developers, I'll pirate it instead" a valid alternative.
I can't think of any "obvious" reasons, actually. They're not going to improve the graphics and there was no slowdown or anything in the PS3 version, so there are no aesthetic reasons for the port. Plus it was built with a controller in mind, so keyboard+mouse won't allow for better controls. There isn't even any guarantee of better online capabilities since the game's multiplayer is limited on purpose by the concept. Basically, the PC version will be identical to the console version except for new areas and enemies (none of which people signed the petition for).
Have you actually played the PS3 or XBOX360 versions of Darksouls? The slowdown in some areas is near unplayable.
I have a copy on 360 and, in addition to loving the game and wanting more content, I want it on the PC specifically for the hope that they'll fix the slowdown issues.