This change doesn’t appear to have been announced anywhere but the Partner Portal.
Surely others missed this too! It’s too late, but go and add your thoughts in the portal link.
At quick gance I’d say these new guidelines impact 20-30% of apps:
Bestsellers: 27% (8/30 apps)
Spotlight: 23% (7/30 apps)
Rovo: 23% (5/22 apps)
Rising stars: 23% (7/30 apps)
Atlassian Ventures: 10% (7/68 apps)