I think that to much customization possibilities are not good. If you let the end user decide about every single UI element that will become a big mess in two ways IMHO. (1) the user will get confused. I mean designing the UI is the (difficult) job of UI designers and you cannot expect every user to have the skills to do that. (2) In my experience such customizations are a huge source of problems and bugs and a real pain in the *** thinking from a developers point of view.

So in my opinion a well designed layout (or two that is) is superior to a badly designed customizable layout. And speaking about porting the application to other devices I think mikhas is absolutely right when he says hard-coding the layout for a few devices is still better than designing it open enough to fit for every possible device.