I've been a fan of the original since childhood... so much so that I bought the 20th anniversary DVD release 8 years ago. I've been amazed over the past year at how many people around my age have never heard of or seen the original.
However, I think they made the sequel in such a way that it's not necessary to see the original, and honestly, trying to show the original to people these days would probably only hurt the franchise. It was ground-breaking at the time, and I still love it, but I loaned my DVD to at least a dozen people over the past few months in preparation for the sequel, and most of them came back saying... "Eh... it was ok. I guess it was probably pretty cool in 1982."
Most people are jaded, and just can't appreciate the original. Even the sequel isn't that strong on plot, and mostly relies on visual effects and the Daft Punk soundtrack. That being said, I still really enjoyed it (even though we drove to New Orleans to see it on Imax, and the screen we ended up watching it on was no bigger than any normal theater these days. I'm really not sure how they are getting away with calling themselves an Imax theater!)