As you say, nostalgia is a powerful weapon. This episode would have gotten a 2 or a 3 tops from me without the Enterprise D, but even I was pulled in by that, and so it got more than it was deserved based upon my genuine love for the glory days of TNG and all that was within it.
As we've seen, though, nostalgia is a funny thing. Give it 5 years, and a few people might say "meh, the last season was kind of shit." Give them 10 years, a whole slew of new series, and suddenly people will long for the days of Picard season 3 and its touch of home. It's cyclical.
For some people, reliving the best days of TNG with a new threat was more than enough to make this the best Star Trek they've ever watched, and that's perfectly okay. You won't feel that way, I won't feel that way, and others won't, but that's the beauty of it: we can dislike the direction the series took, and it doesn't really affect us outside of the normal fan issues we have with such things.
Look at all of the happy people, though. Look at how happy so many here are, how much it moved them, how many it brought to tears, and that's not even counting the series finale.
So in the end it won't really matter. Just take the best you can from it and let the rest go (outside of discussion, of course, otherwise there'd be no point in reruns).