I saw final release footage of the Huntsman Copse area that was featured in the PS3 Beta, it's completely different in terms of lighting.
Whatever mood there was is significantly diminished, you don't need to carry torches because it's now pretty easy to see in previously very dark environments. It's just missing a ton of lighting effects and it really destroys alot of the atmosphere.
That's the main issue, it's not about texture resolution or that kind of stuff, it's about the fact that the lighting is one of the most important aspects in terms of setting the tone and mood of an environment. What was once a moody, dark forest becomes a kind of flat lifeless collection of trees.
What truly sucks is that it's clear that the game was developed with a different lighting scheme in mind, they had it running on PS3 and the framerate was acceptable for a Souls game. It doesn't even sound like the downgrade improved things in that regard but it clearly butchered the look of the game. Certain areas were built with the need to carry torches in mind, doesn't even seem to apply any longer, visual downgrade has gameplay ramifications.
I hope we get to play the game as it was intended at some point atleast, maybe the PC version won't suffer from these unfortunate downgrades.