Oh, one problem that we are going to run into is that APRS has a fixed limit of six characters for the call sign. All GMRS calls are seven characters. That might cause compatibility issues with existing software, many of such is woefully outdated and unmaintained, even if the standard itself is updated to allow seven.
I've been learning about APRS and would love to have something like it widely used on GMRS/FRS. It would make things a LOT easier with emergency community coordination that I try to work in.