You have answered your own question...Something that i find much more of a limiting factor than the roaming issue is the fact that the LTE Watch can't be set up with anything else than an iPhone.Why can't i have it connected to an iPad or MacBook? I hope at some point the Apple Watch won't be dependent on the iPhone, because with it being able to have its own connection i could live without the iPhone entirely.
Apple aren't going to let people obsolete a $700-1000 device with one costing half as much...