I think some of the clues in this crossword are definitely unacceptable. I don't think they're all that difficult, but very lazy and self-indulgent.
However, I would say in response to the last comment that I have won the Guardian crossword prize 6 times altogether, on average once every 4 years or so. Although the last time I won was about 5 years ago, I did once win it twice in a row!