>>1481912Really, I think Madoka's character progression is central to the themes and intent of the show (it's examining and deconstructing the Mahou Shoujo genre, in particular tropes like the power of friendship, selfless wishes, the power of the heart/love, etc.). Rather than being just a Deus ex Machina, Madoka's decision is a complete reconstruction of these themes, and is the culmination of her development throughout the anime.