If you want to stay close to Posix, IMHO you should retain main, perhaps even with (compile-time constant) argc and argv there, too. And perhaps also allow main to return (only to be called again, perhaps), or call exit, to reboot the device.
If Posix-compliance is not a strict goal, it doesn't really matter what you want to call the entry point to the application. You have to document anyway, carefully, what happens before the application entry point is called, as there is no single right way in the embedded world.
--Pekka