Transition plans suffocate a framework. If you have a program and a key leader leaves, you need a transition plan. You need something telling certain people to do certain things. Checklists that are measured and accurate.
Instead, a framework provides markers to navigate with. It's not exact nor is it always predictable. Most of the time it's contextually driven and it will usually force your team to be more engaged.
The choice is yours. And you still have time.