One of the points
" That won’t change whether there’s a 1.3 billion tonne unhatched egg up there or a 1.3 billion tonne corpse." - I believe that this was the point. If the egg hatched and buggered off, then there was be nothing. We needed the 1.3 billion tonne corpse to keep things running on earth.
Someone has probably pointed this slight issue out already, but I'm as disinterested in the comments as I am in the program these days.
The script writing is bloody daft and the attempt to go back to a dark doctor is to appease a past audience; while ignoring the audience of the future who want a more energetic, slightly bungling doctor. Talk about sawing your leg off at the knee to solve an ingrowing toenail.