First of all, a massive congratulations to the Doctor Who team in Cardiff. While debate rages on over whether David Tennant really has made his last Doctor Who appearance or not you have to be amazed at the fact that BBC Wales have managed to keep all this quiet.
When someone dies in Corrie, Eastenders or even Pobol y Cwm - everyone knows about it. Pictures of the crash/murder/fire (no-one dies of cancer in these places do they?!) will have been plastered over Hello and OK (or at least Golwg!) and the only question left for those watching the programme will be whodunnit?
If David Tennant's reign really is over then the amount of work the production team have gone to in announcing his new contract, having him on set while filming the Christmas special etc is astonishing. It would be a work of genius to be honest - catching everyone off guard in a major TV series is hard enough, doing so when people have been talking about Tennant leaving for at least a year is incredible.
On the other hand, if there is another twist to the tale in the final episode and Tennat is here to stay (and unlike Ordovicius and Peter Black I suspect there is such a twist, there must be a reason we keep seeing that old hand of the Doctor in the TARDIS) BBC Wales and Russel T Davies still have to be applauded for keeping everyone guessing.