It's not needed, and I don't think the concept would work as well with 1985.
This, of course, won't stop someone from trying. The problem is the original trilogy was the Michael J Fox and Christopher Lloyd show. They were the ones that made the films work (if you don't believe me, try to imagine the films with Eric Stoltz as Marty, as was originally planned). Now, i could see the potential of doing a fourth film with Fox and Lloyd, except that as we know Fox has had major health challenges and while he still works as an actor (and good on him), I can't imagine him being able to do another turn as Marty McFly. So they'd have to introduce a new pair of actors, or maybe pair Lloyd with someone else -- very risky.
All that said, it has been 25 years since the first film (incredible to imagine), and given Hollywood's timeline for remakes, it's actually overdue for a do-over. I just don't know if people will take to a time-travelling Smart Car the same way they latched onto the Delorean...
It's just as brilliant an idea as remaking Space: 1999 in 1999 or 2001: A Space Odyssey in 2001 (They'd probably had to have to called it 2001: They Don't Go To Jupiter And Hal Doesn't Go Nuts, It's All Rather Uneventful.)
LOL (sad but true). There actually was some talk of redoing Space: 1999 about 10 years ago, too. Fortunately sanity prevailed, and we got the Message from Moonbase Alpha mini-episode that year instead. I think 2001: A Space Odyssey falls into an "untouchable" category. There are a few films that Hollywood studios, though they may be rumoured to be thinking about it, ultimately shy away from remaking. There's a reason the Casablanca remake has never happened. Nor have they attempted a remake of Gone with the Wind (a sequel, yes, but that doesn't count). Or Citizen Kane. Nor has anyone even considered remaking any film that had Chaplin's name on the credits (even though the Great Dictator would be easy to update for today, and The Immigrant would have made a great Robin Williams vehicle 20 years ago). The Wizard of Oz technically falls into this category too, because while the original book has been readapted several times, the original 1939 musical has never been remade (The Wiz doesn't count as it was a new score). No one will ever attempt to redo The Godfather. And while it will continue to influence the look of movies forever, I don't see any likelihood of someone attempting a redo of Fritz Lang's Metropolis anytime soon except maybe as a CGI experiment in 3-D.
2001 is one of these untouchables, and the fact the sequel 2010 didn't do very well at the box office has probably made the studios shy away from tackling the original again - or doing any of the other books in the series.
Alex