I absolutely agree, although I'd also like to know why every new adventure game has to chopped up into episodes so that the feeling of acomplishment is just.. gone! Spending a couple of hours on an oldskool adventure game was epic and you'd get an overwhelming feeling of success when you complete them. But when I tumble through episode after episode I just feel sickened and rewardless. And a lot more skint then when I started out.
But enough about that, the graphics on the older games tend to be more aesthetically pleasing to me than the new ones, I can't explain why but it's probably just Nostalgia.
Also I see what you mean by the games looking bland. Because when the S&M games came out I thought the excat same thing. The dull textures on super round 3D movies is not as exciting as a manic looking pixelated Lagomorph. The retouch for the Secret of Monkey Island looks fantastic. And I wish that was the style everyone went for.
But you're absolutly right, your game doesn't need to be 3D to sell it. In fact 3D technology is old, it may be better defined in this day and age, but it's still all the same.