Loved the show and the finale. The thematic richness, the visuals, the acting, it's all great! Halbrand was written as such in that if you go back and rewatch the show everything he says works for both him (if he'd turned out to not be Sauron) and Sauron. In the books, Sauron was once penitent and could've maybe turned towards the light before falling further, so I can totally believe that this is his soul-searching period and he was attracted to the light in Galadriel, as she was attracted to the darkness in him. He always planned to rule but this was perhaps the time where he could've been tempered if Galadriel had stood by his side (though I'm glad she didn't).
Nitpick 1: I really wish they'd spent at least 1 more episode of Halbrand in Eregion, corrupting Calebrimbor and arousing Galadriel's suspicion. I feel everything moved too fast, there. One assumes Calebrimbor will not heed anyone's warnings and will stay in communication with Sauron since he's meant to also have forged all the other rings. So lesson not learned.
Nitpick 2: Galadriel keeping the Sauron thing a secret. I just don't think she'd care about telling people and taking a brow-beating, and would rather work to unite everyone and hunt him down.
Nitpick 3: Within the context of the show, they really need to make clear exactly how forging 3 rings helps elves. Like, sure, the mithril can reverse the damage to the tree, but how does it help the entire elven race beat mortality if three people are wearing new jewelry? Also it would have helped to actually show the elves suffering somehow, not just the tree leaves turning colors. Make us believe they're in REAL need. It would give urgency to the Khazad-Dun scenes, for one.
Observation: I really don't think that's Gandalf. Although the show is massively compressing the books' timeline (wherein Gandalf arrives much later), I still think this is one of the blue Wizards who, in the books, went east to Rhun and failed in their task to subvert Easterlings away from Sauron.
Looking forward to Season 2. Of the three fantasy shows this year (WoT, HotD, RoP), this is definitely the most well done and my favorite.