When web/gui interface eases mgt and access to the app functions, IMO, the support of a certain type of command line interface completes a "product" (as server app). By large-scale deployment, I am implying that it's impossible to manually drive the apps. when there're many instances of same deployment ..
You're rigth about the EAI concern .. and a file based app-app interface is very useful, in addition to RMI/SOAP i/f. - and that's what I call "scripts" - e.g. for upgrading 100s mySQL databases.
I totally miss your point (could be me) but 'many instances of the same deployment' is no problem with jBPM since it is deployed to a DB. I aslo do not see what you mean by 'upgrading 100s mySQL db' for which you think you need a file basaed app-app interface (what is that?)
Besides that, I disagree that a command line interface completes a product. IMO it is 'old-school', but that is mu opinion and not necessarily that of jBPM
i am also not yet convinced of the need for a command line interface to jbpm.