PADS does, or can import/export, everything in ASCII: library parts, the entire library, schematics, ECOs, PCBs. Many other pcb tools can import PADS ascii files.
It will also create common footprints, including BGAs, with a few clicks.
The ECO generator compares two schematics and generates a differences file in ascii, which can be imported into a PCB to update it to the newer schematic. I don't understand how that is possible.
We have some pretty good procedures for controlling the evolution and ownership of schematics and PCBs.
John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics