Same problem with the Harrier. Loiter time was minimal because the vertical take off gear was heavy and bulky. Only way to resolve that problem (20 minute loiter time) would have been if they had made the fighter much bigger. Even then, the conventional version would still have had an advantage, assuming they shared more or less the same airframe.
Yup. No matter what you do, all things being equal you still have to lug around the vertical take offer gear (nozzles or lift fan) and that is weight that could have been fuel.