I don't see it as destroying the past at all. The two examples I always hear is that it destroyed Luke's character and space combat via the hyperdrive ram, neither of which I can agree with. Honestly it's like saying the prequels ruined lightsaber combat... doesn't make sense to me...
Don't get me wrong, there are plenty of valid criticisms towards the movie, mainly that 80% of the plot was just filler, and everything to do with Leia, but in general it's a decent Star Wars movie that hopefully will pay off even better with the next one...
Unfortunately I just don't see it as a decent star wars movie.
edit: I do find it weird that you can be destroyed for something that you said a few years before that barely anyone got freaked out about. I can understand getting heat now for typing something stupid but the landscape has dramatically changed in just the last 5 years and folks usually adapt to those changes for the most part.