They could get away with this in the sixties. Now? Ridiculous. This would be a kick in the teeth for all Doctor Who fans above the age of ten. A huge part of Doctor Who is its history, its continuity. Take that away and you neuter the whole concept. There is no way this could be canonical and I have no faith that they would stay true to the series' concept. Then again, Russell T. Davies has never really hidden his contempt for the fans of the classic series.
If there is to be a film, it would need to be the CURRENT incumbent of the role, whoever that would be at the time. Or Paul Mcgann. It would also have to be a British production and at leastly partly overseen by the showrunners.
That, said, I think this particular rumour is just that, a rumour. I don't think for a minute that RTD would be able to convince someone of Johnny Depp's profile anywhere near this. He is an anglophile though...
tl:dr, NO NO NO NO NO NO NO. NO.