Barris was my MVP for GW, and you'll find many past posts from me extolling her virtues.
However, the GW changes, the introduction of protection, and finally the arrival of mods, mean she has been pretty much permanently benched on my squad.
Her healing, with of course the right mod setup, is amazing, but realistically as you climb up the power ladder and start facing at least 3 top "meta" teams, her usefulness and effectiveness diminishes.
I can't speak to her performance in Squad Arena as I don't use her there - nor do I see a use for her in raids. Heck, I think she even stayed on the bench for the Jedi mod challenges!!
I think she's got her uses in early to mid game, but by the time anyone has farmed her up to 7*, she's outgrown her usefulness. She was a great antidote when Darth Sidious was meta (remember that?) and his heal block would be a death knell.
As the game evolves, and new toons are introduced, it's only natural that the older ones will either (a) be mothballed, or (b) get re-worked to stay relevant. As Barriss wasn't really a fan-favourite or prominent character, I strongly suspect she'll just fade into obscurity; she has already faded well into mediocrity.