I actually find that most of the changes made on the final album were for the better, or didn't make any difference at all.
YOM is only marginally better in demo form, and either way it's not a good song. The Hollow Years pre-chorus makes no difference, but I like both versions. Hell's Kitchen turned out much better on its own. LITS ended up slightly better. The rest were pretty much the same, and I don't care for the songs that didn't make the cut, at least not enough to replace what made it onto the album.
All in all, I think the album turned about as good as it could have been, and is one of my favourites. But it is interesting hearing the demos and seeing the progression from demo to final album.