I think one big problem with discussing what/if this is a new edition comes from the history of the game where a new edition can mean very different things. I've written that I think so far this is a ".5" edition, but I was discussing with some old grognard friends who pointed out second edition to me.
I call it a .5 edition because the core rules of D20 + proficiency versus a target and bounded accuracy are still in place. The "core rules" of the game are staying mostly the same as far as what I've seen. What is changing, to a varying degree are classes and spells. And that kind of summarized 3.0-->3.5 very well. But, it also describes AD&D1 to AD&D2 as well. The core rules of play really didn't change that much but classes were tweaked and added or removed too. I would call 2E a sort of 1.5 E as well, but TSR didn't.
I think it's fair to say that then next D&D will be as different from 5E as both of those editions were, so you can be correct to call it either way. Unless you're saying the final and only authority on what an edition is ... is whatever the publisher says, I don't see how you can call it the same edition.
Why does this matter? It's because a lot of us are considering whether or not we're buying new books. Ironically, for me, the people who are saying "it's the same!" are also the ones most on board with the changes. They're making the argument for me not buying new books, and that doesn't fit with what they seem to want.