All I can say is that they make re-casting Doctor Who (the time-lord and the show) seem far easier than ought be legally allowed. 

Excellent selections thus far. 

But I do think they've done a bit of deck stacking.

Billie Piper, Eccleston and Tennant might seem like fortuitous happenstance oriented casting to us here in the Americas, but anyone in the U.K know is awares that even Billie Piper was coming in from a major adolescent-pop-star background in England (I have one of her albums, femme pop-club-dance, UK Britney Spears'ish in stature *pause* tell anyone and I shall have at you) and Tennant and Eccleston both light up the any stage they're on. Obviously.

Nevertheless, considering how wrong things can go when casting and chemistry is off and how difficult it is to have lightening strike twice in the same place so soon, It's almost embarassing how well cast the show has been. 

The Avante Guardian. ---- Einstein's Hair^2 //Approved.