http://news.cnet.com...s-mozilla-says/If we enabled the broad porting of existing code we would fail to deliver on our commitment to longer battery life, predictable performance, and especially a reliable experience over time. The conventions used by today's Windows apps do not necessarily provide this, whether it is background processes, polling loops, timers, system hooks, startup programs, registry changes, kernel mode code, admin rights, unsigned drivers, add-ins, or a host of other common techniques.
Our work will get even more difficult, perhaps even considered as "clandestine" or not available to end-users if only "toy" programs from the Windows Store can be installed on devices.
Things like running programs with admin privileges seems headed to the need of "rooting" the device as needed on current smartphones for google and apple.