Brundlely, you've articulated my own feelings about the show much better than I could.
In spite of the couple of issues I have with his work, I do count myself as a rather larger Mike Flanagan fan (not counting, of course, the disastrous baton pass of The Haunting of Bly Manor to his stable of co-creators), because, as someone who once wanted to make films for a living, I can't help but admire the ambition he has (and which I clearly lacked to succeed in the industry), evident even back in Absentia, and the mature level of craft he brings to and elevates genre with.
And while MIDNIGHT MASS, in many ways, contains some of his most mature writing and directing, some of his worst indulgences are right there with them, and over a seven hour period, the indulgences tend to overwhelm. There's an affectation to the dialogue (which, as you pointed out, are really monologues), that creates an artificiality around the scenes, and that removes you as a viewer. There were many times during the seven episodes I sat there, both, loving what I was seeing, and wishing it would just fucking end already. Or at least deviate from the character delivery pattern.
All of the actors are very good, with knock-out work from Hamish Linklater, Rahul Kohli, Robert Longstreet, Zach Gilford and Annabeth Gish.
Katie Siegel was fine, but I think it may be time for him to stop Egoyaning, and casting his wife in things. I'm glad they love working together but, to me, she is consistently the weakest link in his works, and I can't help but wonder if I would be more engaged by her character(s) if there was a different actress delivering those lines.
But even though Midnight Mass is just
his reimagining of King's Salem's Lot
it creates a juicy atmosphere of dread, and it ends on a very emotionally satisfying grace note.
So, I guess in the end, I loved it still, even though I also slightly hated it. Go figure.