I hated the backstory. It was so unnecessary and put this weird American gloss on the whole thing.
There doesn't need to be a backstory -- Willy Wonka is a candy impresario, full stop. That makes perfect sense to kids -- who wouldn't want to do what Willy Wonka does? -- and Roald Dahl was great at speaking directly to kids without grown-up explanatory nonsense.
Maybe hampered by the backstory business (and those huge, horrible teeth), I think Johnny Depp was OK but not great.
The overall look of the movie was pretty cool, and I did like the Oompa-Loompas and their evil little dances. That hit the right note of cute/ appealing and menacing/ evil I think.