@Sven Groot: As if someone went and redid all the textures. From what I read they maybe did a bit of batch-style photoshopping at most or scaled them up such that the algos in the game would not crush the detail so much. (theory: I think that some of these 3d engines/drivers have similar effect as a lossy compressor would - there's various levels of filtering involved that may have variying degree of visible result depending on texture source and internal resolutions - this would explain the results I talked about where games were hacked to render at eg. 4x res and then the output was scaled down back to 1080 res with notable differences - such internal "resolutions" are also at play when doing stuff to audio, that's why synths may internally use higher sample rates etc)
Bottom line: bunch of after-the fact algorithmic post processing on both textures and effects, can infact notably change how good the game looks (I tweaked skyrim shaders for 2 weeks using ENB and it looks like different game, kind of like a video/photo of a CRT running 320x200 game shown on LCD can look better than same game in directly playing on the LCD). The tricky bit here is that people who are this level of perfectionists and artist-type have low chance/desire of getting through any level of interviews (even if they sought a job, artists rarely do as 9 to 5 just isn't for them or me) as by definition if you are perfectionist you tend to value your opinions way above those of non-perfectionists. I think one needs some of that to be a great artist. I do change my opinions very quick if facts support doing so - but in subjective matters like art where it can take years of work to break through to public consciousness you just need to keep improving your own style. Producers are a bit different here as they also look at what the public might be interested in, avoiding the too esoteric / forward looking stuff etc. That's why I think artists need producers and technical people also to get something great & consumable done. Very few highly successful total one man shows out there.
In somewhat similar note, I read about a company Microsoft etc use that hires autistic people to do QA as they are apparently way better in it. Of course they probably only pay 50% of the salary as they couldn't get a job elsewhere, while charging MS who knows what for that 10x improvement (or so the company claims).