Absolutely loved this episode.
Jonathan Frakes directed and also put in one of his best ever performances as Riker, what a pro. I don't think he's a changeling or Tom Riker, he was completely in character. This was the tense, under-pressure Riker who could be an asshole, not the easy-going, jazz-loving womaniser. We saw that plenty on TNG but tends to get de-emphasised lately.
Gates McFadden probably also had her best ever scene as Beverly. I think that was brilliantly written and performed by her and Stewart, as it needed to nail it for us to buy it. I went with it - Picard would definitely have been a shitty dad.
But he was completely right that she should have given him the option to be there at all. In the end they both made bad choices. It was a great scene.
And Michael Dorn very much still has it. He stole every single scene he was in! The chemistry with Raffi is excellent too.
So it's Changelings, or rather, some Changelings. I'm glad to finally have a proper DS9 follow up, and now I'm speculating about some of those rumoured surprise cameos.
A trip to DS9? Colonel Kira? Dr Bashir? Garak?! Probably not, but it looks like the Defiant might be docked at Geordi's space museum.
I'm not quite sure if the Changelings are the ultimate big bad, yet. Doesn't feel like Picard ever had much to do with them, so I think it's just a part of the puzzle...
Appreciated the oblique Odo reference. RIP Rene.