Yea, originally Jenna Louise Coleman started in The Snowmen
, and then they decided to write her into Asylum of the Daleks
and had to do some rewrites to The Snowmen.
So, I imagine, the inclusion of Oswin in Asylum of the Daleks
, led to having her die again in The Snowmen
, which prompted a rewrite to update Clara to modern Clara in Nightmare in Silver
One Day I hope to be the Man my Cat thinks I am
Where are we going? And why are we in this Handbasket?