Although I'm no Ferrari fan I do think they'd be a significant loss to F1 as they have a massive fanbase globally and an equally strong commercial force inside the sport, which would be felt when gone.
This is just posturing at the moment, which there's a lot of in F1 at the moment between the FIA and teams but I think Ferrari would be stupid to pullout as they gain so much from being in it. They've been there since the beginning and not missed entering any races so I'd be surprised at the moment if they did actually pull out.