Classic games are generally not as easy to use or user friendly, and are often frustratingly difficult either by design or by accident.
Nonetheless, I think some of the gameplay they offer still isnt matched in today's games. I dont know what it is exactly, I cant put my finger on it. What makes a game like Baldurs Gate 2 a classic where as Dragon Age 2 will be forgotten in a year? Is it simply that there are more games and we have more choice? Could the same be said of modern movies - that there are no classics generated anymore?
I do think games were more adventurous back then, and I think for a lot of them, thats why we love them. Syndicate is a good example - in its modern incarnation, its being made as an FPS, because FPS's sell and everyone understands them. Maximum target audience, maximum money. Whereas, Syndicate the original could be viewed as an experiment. No one knew if the market would like a dystopian future in which you were practically the bad guys. It combined tactics and strategy, it was pretty violent. There was no market research done, no precedents, it was not a sequel. Yet it was made, it sold, it became famous.
I think the nature of games has changed as the industry has changed, and its mostly the injection of modern corporate thinking into development. Which is to say, avoid risk, go for what you know, what can we get out of it? This is why we dont get games unless publishers think they are bankable, which inevitably means they must appeal to the lowest common denominator. A partially non linear RPG based on a complicated AD&D ruleset set against 2D backdrops with virtually no 3D graphics? Nope, not interested. There goes Baldurs Gate 2.
Maybe the only "classic" game (and its not even that old) that could still be made today, exactly as it was except for graphics and still sell, is Diablo II. Which is probably why its getting a sequel.
@Veliko
They are more playable but less innovative. Thus they have no staying power because they arent unique.