Yes, definitely opinion is mixed. I do miss some of the stealth action of the earlier games, but at the same time, I also do enjoy action RPGs. Both Odyssey and Origins are grindy, true, but for me, it's the wonderful worlds that made it worth exploring to the point that I didn't really notice any grind. The problem is, most people aren't interested in random exploration, they just follow the story and markers. In which case, yes, it can be grindy. Though with Odyssey's later patches, they have added options to ease that, with the enemies scaling easier if you choose.
The good news is that Valhalla goes back to some features that were lost, while retaining the best RPG elements. It's clear that they want a more focused experience with Valhalla with much less grind.
Totally agree with what you said. They won't feel grindy if you do a lot of exploring, but that hurts the pacing of story in my opinion.
Excited for Valhalla~