or just make 87.70 a FM Frequency
To some degree 87.9 is. http://en.wikipedia.org/wiki/KSFH
But everybody wants a slice of the FM pie. Canada is moving all it's AMs to FM, so is Mexico and South America. We're talking about the entire Western Hemisphere. And the UK is already trying to deal with it's own FM crunch. Even though they want to move everything to digital, I don't see that happening. Like in the US, there are too many terrestrial obstacles that make digital very hard to receive in many areas. The rest of the world has the same problems.
There are some areas where AM has a distinct advantage over FM (deepest Alaska, very rural and SEVERE terrain challenged areas.) So in those places at least, I wouldn't write off AM just yet.
But the expansion down to 76 MHz DOES make a lot of sense. And I also support an expansion UP to 128 MHz (I know 108-128 MHz is reserved for aircraft, but I have RARELY heard ANY activity on these channels.) Because EVERYBODY wants to have a place on the FM band....A 76-128 MHz Super FM band should have room enough (and then some) for everybody.
As for LW, well it too has it's place. And there's not much you can do with it but have fun. Make it AM Stereo and should we colonize underwater, it should have a ready audience......