[Request] Make phone app more responsive
 

Is it possible to make this app more responsive? As far as I know the phone is not clocking up when the phone app is being used.
My particular problem is hanging up after I made a call. It takes some time for the app to show up (switch on the display) when I take the phone away from my ear and again some time to respond to me pushing the hang up button. (My phone is locked to landscape, so there is no transition messing things up!).

Another problem are apps that use a lot of resources. When I use my phone as car navigation system, I cannot except calls because the navigation app (Mappero) hogs the CPU. I'd like to prioritize the phone app over everything else!