In 2D drafting tasks and responsibilities were usually allocated on a drawing or document basis - Plans, Sections, Elevations, schedules etc. In BIM projects drawings are done automatically so tasks and responsibilities need to be applied differently.
As the Revit model is supposed to be a Virtual Model of the real building the best way to allocate tasks is by splitting the building up into functional parts.
It also good practice to make team members responsible for the complete design and documentation of those parts. No-one just "models"; if responsible for wet areas that includes plans, RCPs, internal elevations, details, legends, fitting schedules, finishes schedules etc.
Setting up the project.
Setting protocols for the project (based on Office protocols).
Checking warnings.
Managing views and sheets.
Managing Schedules.
Setting up basic views.
Setting up Sheets.
Setting up Schedules.
Setting up View Templates, filters and other visibility tasks.
The number of parts will depend on the size of the team, project and stage of project.
One person may be responsible for multiple parts, but if multiple people are working on one part only one person is made responsible.
Building parts typically correspond to Worksets or Linked files.
STRUCTURE (until Structural Engineer model is provided)
BASE BUILDING
FACADE
WET AREAS
STAIRS
FITOUT
. . . etc.