First, let me tell you that I honestly don't think that new games are worse than retro games. I can enjoy a new game just as much as an old one.
That said, I actually like the new Syndicate - not as a game, mind you, but as an experience.
But old games often have a certain charm that goes beyond nostalgia. I think you can feel if something is "hand made". I think that's why the indie-scene is so successful with their pseudo-retro games.
It's a little bit the same with movies: People always want "despecialized" versions of Star Wars, for example. Not just because Han shoots first but because all these hand made special effects are much more charming that the soulless CGI of the remakes - even if they don't look that good.