[Quiet Man Cometh]

Dunno. It's hard to judge for me because of the tiny details that had significance in the larger backstory that is Middle Earth and I'm not sure how those little details would be interpreted otherwise, unless hypothetical Jackson had larger stories in mind from the get go. I know when he was editting the films it was a given that there would be an extended edition on DVD so he cut certain scenes, knowing they would come up later.

We'd have to think back to the start of fantasy literature though, since, assuming that Tolkein wasn't around in the first place, it's likely that contemporary fanasy novels would be different. It would certianly have an effect on today's fantasy literature that might make imaginary new LOTR more significant.

I suppose one would have to decide how much influence writers like Ursual Le Guin, Susan Cooper, Steven Donaldson, Joseph Campbell (not fantasy but I would say important), etc. would have independant of Tolkein to decide where the current state of fantasy writing would then be.