IMO the argument that we shouldn't criticize online AH threads because they're not professional and so criticizing them isn't fair falls apart given that we are also in the online AH community. If you post a story in the online AH community it's fair for online AH people to criticize you for it. I do however think there are three criteria that make an online AH story worth criticizing (I'll use Queen Nixon as an example of each criteria because this thread has talked about it to death)
I used very similar criteria for deciding to go ahead with my Fuldapocalypse review of NDCR. I
was obsessed too much with the WW3 TLs that weren't really that bad or distinctive in hindsight, and a big part of the blog was so that I could examine fiction with a higher standard. Because I didn't want to backslide, I thought very carefully.
First, it wasn't that it was intended to be finished so much as how the arc with a clear ending that I was most interested in (the WW3, obviously),
was finished, and had been for quite some time. I felt a lot more comfortable looking back at something ever-more in the past calmly than I would be with something in the middle.
Second, I felt like I could say long, reasonable calm (if still extremely critical) things about it. Because the WW3 was legitimately distinct, I could talk about how that was different from other conventional WWIII stories, and because it embodied (to me) so much of the flaws with online AH's style in such a massive way that other TLs didn't, I could use it to illustrate those flaws. I felt it wasn't emotional axe-grinding and did have substance. There was that and there was the blog being so established that I felt one post on an online AH, especially one very pertinent to the founding subject, wouldn't get in the way.
I ultimately reviewed NDCR because, long after the "Turtledove Drama" stopped, it still felt interesting. It felt interesting that it somehow took
all the narrative and research flaws of the online TL format and seemed to amplify them. And it was interesting, especially having read so many more conventional WW3 stories, to see something that not only was distinct and distinctly bad, but had almost the exact opposite flaws that middle-of-the-pack military AH normally did. (Instead of being rivet-counted to excess, it didn't care about numbers or any kind of technical accuracy at all)
But I'm still very uncomfortable and personally reluctant to review more online AH. I think too much of it is just too small and too easy, and it feels like punching down.