BTW open sourcing their app wouldn't make a difference at all, actually it doesn't even make sense.
They can open source the application but not add any new developers outside of the company (which wouldn't mean anything, other than good faith).
They can open source it and bunch of people might send stuff in an un-organized way, it never ends good. There are thousands of open source projects some serious usability issues because no one cares and it's hard organise people in open source projects and consistency is the key for usability. So open sourcing projects in this scale, %95 of the time won't be better than what it's.
I can't even recall one successful product that area.
Although publishing more document, samples etc. about API definitely helps.