Egghead would have been infinitely better if it was an arc like the Flying Fish Riders, Post-Water 7, Post-Alabasta, Zou or even like Gaimon's. Just 20 chapters of exposition finally answering some mysteries and giving the characters a break to train, upgrade and catch up on world events while all the actual fighting happens elsewhere, like SWORD vs Blackbeard. If Oda and Jump really wanted the Gorosei to do something, they could've just had them fight one of Dragon's armies since we know they were sabotaging the food shipments to Mariejois.