I love BTTF2, but it was WAY off when it came to predicting the future, IMO. It completely missed the computer revolution, email and the like. IIRC, future Marty was fired by fax!
Moreover, hoverboards and flying cars and the like would have relied upon some anti-gravity technology that we're not even close to developing as far as I know, and there are no Mr. Fusion power generators or food hydrators floating around, either. Talking houses and biometric locks may be possible, but I don't see them in widespread use by 2015. I expect I'll still be using an old fashioned key to get into my house in 2 years.
It did get one concept right, though: drone technology for monitoring crime, which may well be in use by 2015. But, fortunately for us lawyers, it was way off in predicting the abolition of lawyers.
From the perspective of the '80s when the film came out, it gave a glimpse of what the future might look like, but it shouldn't have been taken as a prediction; it was, above all, entertainment. And it should be viewed in that light.