Honestly I am the complete opposite. Though, I am an anime watcher only, so keep that in mind.

Firstly, the worst critique that I can give SG0 is that I barely remember it.

Of what I remember, the action scenes was one of the things that reaaaally annoyed me, steins:gate was never really about that and here it was at its worst. Wanted to bang my head against the wall during those rooftop ones especially.

And I think I hated the plot twists near the end ?
I don’t remember them but they were just not interesting, to me at least.

I also didn’t like that what made mayuri actually act in episode was a call from herself. It kinda killed a great character moment IMO.
And I only remembered about the romance between Mayuri and Okabe 'cause of your post but, I found that romance so unnecessary and against the original story, they never were in a romantic relationship before. They went through so much shit together but their love was never romantic.

Last thing, I usually really do not care about fan service in anime (I like High School of the Dead ffs), but the boobage size increase across the board left a bad taste in my mouth.

To end this, I want to say that I dont’t think it was all bad, there were some funny moments in the show and it was really nice to see kurisu and some of the characters after so long.
But when someone new to the series asks me, I tell them to not bother watching 0.