Originally Posted by
anabolism
The only policy change (as opposed to how specific lounges interpret it) that I'm aware of is that AA Flagship Lounges, after being remodeled (e.g., JFK) will allow in OneWorld Sapphires, AA Platinums and Platinum Pros, and anyone flying in AA Flagship Business Class (AA's rebranded long-haul business class).
To add to the info
anabolism provided, here's a link to details on
Flagship Lounge including Access policies.
There is also
Flagship First Dining which is available to passengers traveling in AA First on 3-class aircraft (or 4-class if/when E+ becomes a real AA product). Almost identical in concept to BA Concorde Dining at IAD, OWE does not give one access to FFD. There have been reports that those traveling in CX F ex-JFK have also been given invitations to FFD at JFK even though the rules don't specifically include them.