Going too big too fast?

I thought it worked out fine. When you're making a sequel to a movie (and the Duffer Brothers like to think of Stranger Things as a really long movie) you've gotta raise the stakes somehow. However, they have said that Season 3 will be a much more intimate story. 'Less broadening the scope, more getting back to our roots' — sort of thing, I guess. Since Eleven closed the Gate, we'll probably be taking a break from Upside Down shenanigans anyway.

Almost too big period for me, so much as to change the whole tone of the show. I think they could have expanded the threats a la Aliens without completely losing that. I loved that it was a genre show that didn't feel like an apocalyptic scale fantasy-action, but at times in season 2 it was basically flirting with that. My hope is just that they don't feel every season needs to up the ante, and that they won't be afraid to go low-key as well.

I dont think so
The kids are growing up, Eleven is going to master her powers at some point...i thought it worked out well and was just about perfect

I think so. I felt the overall plot was very weak and I just couldn't get into it. Will being infected by the shadow monster and we are given no backstory or information about how this would be possible. Even for Stranger Things, it seems far too unrealistic to me.

I enjoyed most of the episodes that related to Season One.

Seems to me that the writers and directors were panicking a bit, in terms of how to continue the story once the main antagonist is defeated at the end of Season Two...... Hence the injection of the putrid Episode 7, which threatens to turn this series into yet another superhero movie.

The Mind Flayer is basically their ultimate threat. It's a Destroyer of Worlds, God of Death type adversary that seems totally impossible to defeat. This is the enemy you vanquish in a final showdown against hopeless odds at the end of a story. I think the Upside Down menace will be on the back burner next season. They've said their initial plan was for four seasons, which may possibly go to five but no more. So the Mind Flayer will come front and center again and be the focus of the last season. They'll find a way to destroy it in the series finale and go out with a bang.