This has completely broken most of the functionality of RunSyncSwim (our app for enhanced Club Leaderboards).
We used the list of club members to display Club Leaderboards, and a whole heap of additional Club based information/statistics that the Strava web/app interfaces did not provide.
Now that we have no actual details of the club members, it appears as though over a years worth of development and usage (and almost 100 Clubs from around the world were using our site regularly) may need to be scrapped.
We used the Club Admins list to allow those users to categorise Club Members (one of our favourite features was to allow a workplace to pit smaller groups/teams against each other), as well as other settings.
Now, those users can no longer do anything as we don't know how to associate them to the club as an admin (because the primary key of athlete_id has been lost - and many of our clubs have more than one 'John S.' in them, making any other form of matching useless).
On top of this, with Club Member lists now no longer telling us who the Club Members actually are (first name, last name initial is also completely useless), we can't put people in clubs either.