Having given it some thought, I think at least one rule (however small) is necessary. If only because as of now we're all just picking players from the exact same player source, with zero surprises in store.
So we can either do an era based rule. One from each of 70, 80, 90, 00's. Not too sure about the 10's and the 60's wouldn't really work without re-instating the Fairs Cup.
OR
2/3 per winning finalist. Without researching it, the club option could be a clusterfuck.