Like everyone else affected by Robert's wish, Hermione was more than delighted with his new gender. As an organ of sexual pleasure, the penis was everything he had fantasized about before the change and more. And the other aspects of his new gender--both social and physical--were highly agreeable as well, even extending to such trivialities as being able to reach the top shelf of his kitchen cabinets without standing on anything.
There were a couple of, not problems exactly but issues. One was name. Just straight-out masculinizing Hermione got you either Herman or Herbert, which were too nebbishy, or Harry--and Hermione hadn't changed gender just to be subject to more Harry Potter jokes. But once you give up on masculinizing your original name, there were a lot of choices out there, and it was hard to pick one.
The other problem was more complicated, and like other complicated problems in life it had to do with sexuality. Hermione had been a butch lesbian without the faintest sexual interest in men. And as a man he still liked fucking women--a lot. But now it wasn't the only item on the menu. Ironically, becoming a man had made him sexually interested in men for the first time.