I think this document is unnecessary.
The initial motivation was the proven-packager-privilege-revocation issue. But that decision — with all its faults — was not influenced in any strong way by conflicts of interest. The current proposed policy wouldn’t have disclosed anything that was not known to all participants and wouldn’t have informed the decision in any useful way.
I see various decisions taken in Fedora slowly or erroneously (in hindsight), but those issues have little to do with conflicts of interest. I’d name the following reasons: lack of time to investigate details, misunderstandings about scope, preferences for certain technologies or approaches, overambitious plans, tiredness, lack of synchronization, etc. In some cases personal sympathies or trust/distrust between people exists, but those not the obvious types of relationships that would be disclosed under the proposed policy. (To put it more directly: I think that a FESCo member may in borderline cases vote for/against a propal if they like and trust/dislike or distrust the proposer, but not because of romantic or intimate or financial or career relationships.)
I think this proposal is trying to transplant a policy that is useful in other contexts, where personal conflicts of interest can be much more unexpected and can have a much bigger impact, into an environment where pretty much every decision has some potential conflict of interest, but those conflicts are known and unavoidable when we’re all working on a shared project.
EDIT: I referred to FESCo mostly in my reply. But the same logic applies even more to every SIG, engineering subproject, working group, and team.