I've read this specific article: https://www.theguardian.com/media/mind-your-language/2011/mar/07/mind-your-language-ahead-of-before and am trying to figure out why the author wants to change "ahead of" to "before" in the quotes he mentions.
In order not to copy the whole article,here's in two words:
But the craze for writing "ahead of" to describe any forthcoming event, whether far in the future or imminent, has made coming across "before" in a newspaper about as likely as bumping into a recent recruit to the Nick Clegg fan club.
The author insists that using "before" is better than using "ahead of" in the following quotes:
"Ahead of the Christmas No 1 announcement on Sunday, readers define the perfect seasonal hit."
"Speaking at a press conference ahead of his 80th birthday, Gorbachev criticised Putin for manipulating elections."
"Talking to Simon Rattle ahead of his London residency with the Berlin Philharmonic Orchestra ... "
"University candidates are racing to submit their applications ahead of the tripling of tuition fees from autumn 2012."
He then says:
These examples are all from the Guardian and, I assure you, were not hard to find. But "ahead of" mania has gripped all newspapers and is heard more and more frequently on the BBC and other broadcasters.
As far as I see both "before" and "ahead of" can be used.