Whilst I would agree that moving OSMC to a final product would be a priority, in terms of the basic idea of OSMC being a super user friendly easy to install product, I think you need to cater for the masses. Setting the time zone up during install would make a lot of sense as these days most computers/phones etc do the same and by the time the install is done the time displayed (which it is on the first menu you see after install) should be correct IMHO.