Yeah, I enjoyed Liz. But again, with Betty and Ned, does anybody really care all that much? Really? Like, who was pulling for a super 100% comic accurate Ned Leeds? What fan is over there holding up their favorite Ned centric stories from the comics in anger? The biggest thing I remember Ned contributing to the comics was dying in Berlin. So the changes to them I really didn't care about. They were characters that were never centric to the mythos.
For Flash, eh, I can buy it. Bullies today don't have to be the good looking jocks. They can be the rich kids. And Flash was clearly a spoiled rich kid. Is it my ideal version of Flash? No, but it's a close enough take that I think it works.
And yeah, the MJ thing is just odd. Spider-fan, I agree with you. I essentially view her as a new creation, but, again, why muddle it with the MJ confusion? It's just messy. And needless annoys the people who would be hoping that we might see a comic accurate Mary Jane (personality-wise, I could care less about her race) for the first time. Raimi's films butchered her, and now we'll never see her in this. Which is a bummer. But, again, if you don't ever have her called MJ, then I wouldn't be annoyed or putting unnecessary expectations on this character. You keep her as Michelle, you have her be a new creation, and I would never get a tinge of annoyance that they're trying to straddle the line with this "kind of Mary Jane adaptation and kind of not" thing.
And overall, it's just a really weird choice. I don't know why they thought it was a good idea.