Designing and deploying Cisco ACI can be done in a lot of different ways. There is really no right and wrong here when it comes to the deployment model. There is just a list of requirement that best fits the chosen model.
As Cisco ACI has been around for several years now, it got more mature and is been seen more and more in the enterprise market.
I’ll try to help you decide on how to deploy Cisco ACI in a way that matches your requirements.
The Cisco ACI solution is trying to help you solve certain obstacles while still meeting your requirements to align with your “Business model”.