It isn't. It really isn't. It is as deep, dark and meaty as Twilight.
I don't even know how this is argument. RTD is the man who created farting aliens. Moffat created the Silence and the Weeping Angels. RTD gave us Dobby Doctor. RTD gave us Rose, Martha and Donna. Moffat gave us a married couple in the Tardis. Moffat had his Doctor give the Silence a worldwide execution.
But I would love you to explain it. You keep making these statements, but don't really give examples from the show. 9 yelling at a Dalek that is so close to be being ridiculously cheese isn't dark.
What is so dark or meaty about RTD's work in comparison to River Song, the Weeping Angels, the Silence, "The Beast Below", The Christmas Carol, or how The Great Intelligence has consumed the life of children for over a 100 years? The 6th season is one big dark fairy tale.
The complexity of Amelia Pond, River Song, and now Clara Oswald show far more meat and more depth then anything RTD had going.
Do tell.