Fridge Logic: If the Space Hotel had "newspapers and television shouting about almost nothing else for the past six months," how come we never heard a word about it in Charlie and the Chocolate Factory?
Not to mention that the furore over the Golden Tickets is now a part of the "almost nothing else".
Padding: Among other things, we get the President's nanny singing a song about raising him.
Paranoia Fuel: The Gnoolies. They infest Minusland, are completely invisible, and have a vampiric effect on their victims when they bite them.
Sequelitis: The first half is padded, but at least tries something new; the second half is a retread of the misadventures of the naughty kids from the first book.
What an Idiot: All of the grandparents except Grandpa Joe take four Wonka-Vite pills to become 80 years younger (each pill reducing one's age by 20 years) despite Mr. Wonka telling them to take only one or two apiece. Problem is, two of them were barely in their eighties to start with and one hadn't even celebrated her eightieth birthday yet!
The first book referred to the grandparents as "all being over ninety"; certainly they may have all felt that way, so any offer of youth might be snatched up without thinking what would happen. On a darker note, at first Grandpa Georgina had even considered swallowing six or more pills. Interesting that Grandpa Joe refrained from taking any of them, he had been the only one who'd gotten up earlier.
Grandpa Joe was also the oldest of the grandparents at ninety-six and a half, making him the only one who could have taken four hits of Wonka-Vite and still be of use in helping Charlie run the factory.