Hi Miguel,
Great point.
In my opinion you can devide this issue into 2 parts: 1) the actual deal governance and ways of working and 2) integration of a target company and the correspondent changes on control and DoA. In both cases, if not well defined, it will for sure cause paralysis and conflict, potentially destroying the deal value.
On the Program Governance it needs to be clear who the deal Sponsor is, what are the candence and forums to escalate roadblocks and what can be or not decided by workstream leads.
On the actual integration, the target company and people also need to potentially change some critical processes and delegation of authority within those process (e.g., thresholds for supplier payments approvals, etc) and that needs to be prepared during the integration planning and communicated accordingly.