Hi Tom,
No matter how many guidelines, templates, classes you offer to the BA team, the reality is that every one is different, possess different skills, and has a different style. So trying to achieve perfect uniformity is not possible... I'm sure you already know that.
Is there a BA Leader in the organization who is seasoned and has the capability to provide feedback and coach the rest? If yes, one of the best way to accomplish your goal is to have the BA Leader (Master BA), review the deliverables from all other BAs and provide feedback. The Master BA would not herself/himself create any artifacts but focus solely on providing feedback and guidance.
This will not only help you achieve greater consistency of requirements documents but, even more importantly, it will ensure a cohesive set of requirements and design:
* ensure there are no duplicate requirements (multiple BAs working on the same thing)
* ensure there are no conflicting requirements (different BAs documenting requirements which cannot all be implemented at the same time)
* ensure the overall business process and design is consistent so that that parts work together as a unit to achieve the ultimate business goals/outcomes.
Let us know how you end up solving this challenge.
Adrian