Well, I'm re-reviving it because a comments site was discussing Broadway shows that have "dated" versus "timeless" ones and I mentioned "A Chorus Line" in passing as one of the former. So someone asked me why--specifically--I think it's dated, and I had to think about it and wanted other people's take, because i wasn't sure how to articulate it. The obvious stuff about costumes, dance and cultural references weren't enough because you can just update those things or present it as a period piece, "It's 1975, get over it." The latter option is best, I'd think, but I think it'd come off uncomfortably--maybe because the era isn't distant enough. A few years ago I saw a revival of "Private Lives", with its totally outdated dialogue and gender assumptions, etc, and it was easy to say, "It's the 30's, a different time, and it's hilarious." But--as at least one poster said--the "concerns" in A Chorus Line are current, but the way the characters think about them are so 70's.
The poster mentioned "body shaming", and duh, that's right. "Dance 10, Looks 3" was a showstopper when i saw it. Can you imagine a number composed now about a girl having plastic surgery so she can get jobs that would be presented without any larger reference to the "issue"? I can't, and it'd be a drag if it did that, but it would just feel odd that she could sing that as a racy comedy thing and nobody would bat an eye. And that goes for Paul's monologue and a bunch other stuff.
So I think it IS dated. That doesn't mean I wouldn't catch a revival if it was nearby, but I can't see responding as I did in the 70's.