Forget about existing banking interchange formats which (from personal experience) wells fargo both doesnt supportOFX or implements poorly QFX, they should definitley define a new API and be a leading stakeholder.
Banks move at speeds that make most glaciers jealous and Intuit has some financial incentives to keep the spec complicated so it's really no surprise we've been stuck with it so long.
A new open standard would have been nice, but I wouldn't hold my breath on other banks implementing it, so I can't really blame WF for going it alone here.