I have a lot of conflicted feelings too! Mostly along the line of why the hell Merlin hasn't just showed Arthur where Morgana and Agravaine meet ages ago so all of this had been avoided! *sigh* Your idea of at least telling Gwen about magic makes sense too. *sighs again*

I think they tried to justify not telling Arthur with the whole "he won't take the word of servants over that of his uncle" excuse, but there are plenty of holes in that logic.

And yeah, poor Gwen didn't get to have any agency. I'm annoyed too-it's probably due to the whole "family show" thing, where nobody is allowed to have messy human emotions and still be considered a good person.

I did feel for Arthur a lot, even as I felt even more for Gwen.

My theory of where Gwen is will remain my head!canon until it gets jossed!