[KaiserPro]

How it worked for us was as follows:

the business goals were translated into "epic" tickets, after that it was entirely up to the engineers.

An example of this would be something like:

We need an API that allows secure access to service x. It must have authentication, respond with an answer inside x milliseconds, It must work with a developer admin interface (see ticket z)

Ticket z would be assigned to the web team, and we would work closely on an interface between the API backend and the dev interface.

After that, my team would layout and make a high level design. We'd break that design down into individual "sub epics" and let each dev create and work on tickets as they see fit.