The Whole temple of Mythal was a slap in the face for my dalish.
First the was the Whole thing with the geas which was a terrrible choice to make. For my Lavellan being dalish have always been about being free to think and believe what she wanted (a tad naive perhaps, but she truly felt that). Then there was the meeting with Mythal which was not pretty.
Not just where the creators real and not just stories, which mean Lavellan now had to consider all the events of the stories and things that might have actually happened. (Let's be honest the creators are not a nice bunch). Mythal had taken a human host and had pretty much ignored the People's plights while focusing soley on her own revenge. My Lavellan just lost faith in the creators after that.
So while she appricated how current symbolic value of the vallaslin, she just couldn't wear them anymore. The creators were just not worth it. Add to that, after the well she was also concerned that the markings could be used as another form for geas and mind control and I really wish we could have asked Solas about that. (Because I can't be the only one who jumped from Blood writing to blood magic to mind control?)
My Lavellan was pretty much on the same boat as yours. I think she pretty much lost faith in the Creators too, after she learned that they were not a very nice bunch and after her encounter with Mythal, which is one of the reasons she opted to have her vallaslin removed. Though I'm not gonna lie, I do miss having them and almost chose to keep them.
And yes, what you said about the vallaslin being a form of mind control has been something that has been weighing on my mind too. The meaning may have changed, sure, but what if when or if the elven gods return they use it to control the Dalish? I'm guessing it's like some form of slave collar back in the days in Arlathan, though I may be wrong.
EDIT: Also, nice to have you back Caddius! I do miss the little history lessons you used give to this thread.
(And Madrar, I see you there, liking one of my art post, hehehe! Nice to have you back too.)