It feels that there's a recurring theme in yr Who stories about the Dr's big hero moments (The Pandorica Opens, A Good Man goes to War) always leading to a defeat and his moments of surrender leading to a victory... (The Big Bang) Which is Heaven Sent? #asksteven #hellofabird

Steven sort of answered my question here:

I suspect in years to come most people will watch Heaven Sent as a standalone episode without Face the Raven or Hell Bent. That'll be a big mistake, like turning off The Pandorica Opens after the Doctor does his Stonehenge speech or A Good Man Goes to War at Colonel Runaway.