Thanks for the reply Thomas.
For my first point, I just figured the "slave" ESC would simply have the brains disabled and have the primary ESC do all the logic. Yeah, there would be a lot of engineering involved, but just figured it would be an easy way to add more current handling. The ability to use two motors would be more involved to be sure.
For my second point, I do realize these ESCs are for the R/C industry, but there are a LOT of non R/C applications where a low-cost feature-rich brushless controller could be used; pretty much any application where a brushed motor is used could be replaced with a much more efficient and maintenance-free BL motor.
Both of my ideas may not have much marketability (or maybe they would). It's just a wish list for me.