The only downside is that Eric Stoltz was a better match in physical appearance as the son of Crispin Glover, and Lea Thompson. So in that respect the casting was very good.
In your opinion would 'Back to the Furture' be as iconic, and memorable if Eric Stoltz kept his role in the film?
No way of knowing, but I don't think so. It is one of those magic films in which an actor makes it great. Michael J Fox was that magic.
I don't buy box sets at launch anymore, especially if I only watch one of the films included in the set (Indiana Jones, Jurassic Park, Back to the Future etc.).