There’s the third option, that is work together with ERPNext, to dont break the community in chunks that will make everyone more fragile in the longer term! Break the community forking the product is not good for everyone else, except who take the fork initiative!
My suggestion with an ERPNext Community Association
is exactly for we join forces and ideas, finding the middle path, like, it’s okay if ERPNext team, doesn’t want BPMN as part of the core product, but, what us as community can do to lead, support and raise this development?
Instead of forking, we can construct an APP for BPMN, and, create new hooks on ERPNext itself to make that integration better. If after get mature, what started as an plugin become, useful enought, to join the core, it always, will be there for ERPNext take the effort for they join.
Let’s look for Wordpress, for example, what make wordpress, is not Automattic.com, but the community around Wordpress that is always releasing new plugins and themes, to make Wordpress better!
As community, we always should be representatives, so, will be welcome, if we work together understanding what need to change into ERPNext, to support USA, Brazil, Italy, Gana etc, in terms of taxes, but we need to work on this, making one small change per time, but an smart change that allow everyone else tap they own local freaking rules into ERPNext.
But I think this is a subject for another thread!