Not case closed. Given that you lose a lot of useful tools (Interface Builder, Storyboards and such) and that Objective-C can be pretty quick to code with Xcod

Not case closed. Given that you lose a lot of useful tools (Interface Builder, Storyboards and such) and that Objective-C can be pretty quick to code with Xcode I would contend that given expertise in both a complex application would take less time to code in Xcode/Objective C.