I’ve heard Democrats complain that the focus on Clinton or maybe drafting Michelle Obama to run prevents anyone new and good from rising up to that level.
That is true, and I love watching it. The tradition of an ex-president not criticizing his replacement doesn't come from good manners. It comes from the fact that a new party leader cannot emerge while the old one holds the limelight. Every time Obama and Hillary speak up again President Trump, I cheer.