Your "old OS apps are bugged out and don't work" analogy is incorrect. All your apps (vanilla Destiny content, TDB, and HoW) are still there, working as usual and still 100% supported. It's more like you lost access to a couple of features on the phone, like Bluetooth and location tracking (Heroic and Nightfall) because they require a new protocol. That's it. 95% of everything about your phone still works fine. You just can't get anything more for it.