Darvin: One of the biggest changes is that few people read the manual anymore. Old games often just begin with no introduction, tutorial, or even a prompt to tell you what you should be doing. It was presumed you had read the manual already, which contained the backstory (often with far better art that could fit on the limited disk space of the time), instructions, and maybe even a walkthrough of the early parts of the game.
I've hardly read a game manual front to cover in all my life and I'm a pretty old guy. I much prefer games that allow you to jump right into them and learn their mechanics and rules by playing. If that's a modern trait, in my book it would be an improvement. But I'm pretty sure it isn't or else I wouldn't have become a gamer back in the days.
EDIT: I mean, what you describe is true, of course. I'd just say that it's a change in game design, due to the superior technical possibilities today, not so much a change in players or player preferences.