The original (which is the PS3 version in this case) was actually sub-HD. These images are native "full HD" (i.e. 1080p), but as you note they still have aliasing.So was the original sub HD? Also on that note are those screenshots really HD? I'm not pixel counting but I can clearly see some fat and chunky jagged lines all throughout the image on top of some general murkiness.
I'd hope that on PC at least 5k shouldn't be a problem for this game, to get rid of any aliasing.