It can be argued (and already is) that PC is already the "next-gen" platforms. Still, it's been open for debate as to whether "next-gen" consoles like the PS4 and Xbox One will have graphical superiority to PCs. Depending on who you ask, you can always get a different answer, and that's probably because each studio makes its own development choices.
For Infinity Ward, the PC version of Call of Duty: Ghosts will use its own set of assets, which executive producer Mark Rubin claims will make it the best looking Call of Duty game the studio has released on PC.
"PC is taking a different tack from previous games [in the series,]" Rubin told Kotaku. "Now, PC has its own set of assets. It's going to look better than any Call of Duty we've ever made on PC."
Prior to this installment, Infinity Ward, which has made Call of Duty games in odd-numbered years, used the same graphics assets as the Xbox 360 and PlayStation 3 games. Now with next-gen consoles releasing, Rubin assured the site, "They're actually using even higher version [assets] in many cases than on next-gen consoles, from a texture standpoint."
As for gameplay, Rubin said there shouldn't be a noticeable difference between current-gen, next-gen, and PC.
Which version of Call of Duty: Ghosts do you plan on purchasing?
[Kotaku]