I haven't had issues with the mobile apps of 3 of the most major US brokerages. They run fine on rooted phone. They do everything I'd want a bank to do anyway.
Ditch your bank if they have issues. If their retention department asks why you're leaving, tell them their app doesn't work.
This is what I was thinking as well, TBH. I'm not particularly tied to any of my banks, I already did mostly switch off of BoA because their website was so bad.
Good to hear everyone's responses in the thread though, some stuff I definitely didn't consider.
Ditch your bank if they have issues. If their retention department asks why you're leaving, tell them their app doesn't work.