I feel rather mixed on this one.
Cons:
I said in last week's episode that I didn't approve of the Grog choice, and I stand by that here. No matter what direction they went in, it would feel odd and anti-climactic. Here, we get to see that Grog's body is intact, and that life might be able to return to it. So that basically tells me that for these last three episodes, Pike's arc is going to be about whether or not she should accept what the Whispered One is saying, if it means it might save Grog... or if she can find another way to bring him back without succumbing. And that's... I mean, I guess that's fine? But I just keep thinking that structurally, you could do this same story without Grog having been visually ripped to pieces at the end of the last episode. Like, okay, imagine a reality when Grog gets pulled into the portal and he's trapped over there, and then Pike follows him with the others trying to stop her and looking on in horror. Then Pike shows up and the cultists have Grog trapped or under a spell or poised to be the next great sacrifice, and the Whispered One uses that as leverage to have his lore-drop convo. Then, back in Whitestone, the rest of the gang can be determined to go rescue Grog and Pike together, believing there's a chance both of them might be alive. Taryon even says it as he sends them off, telling them to bring their "friends" back. Plural. What would be structurally different if Vex, Vax, Percy, and Keyleth didn't believe they knew Grog's fate already, and thought of this as a rescue mission to save them both? Tl;dr, I'm legitimately not sure what a Grog death does here, thematically, beyond just giving us that really dramatic moment at the end of episode nine.