Originally Posted by
Corwin:
“What is supposedly a Promo Image for Death in Heaven.
Look in front of the Doctor.”
Okay, but I still maintain it's a metaphor. It would be difficult to convey how this version of the Cybermen came about on a promo image - and arguably, it would be something of a spoiler since it's not been confirmed yet in the episodes - so by having a Cyberman's hand raising up from beneath the earth, they're presenting a link between the dead and the Cybermen without explicitly saying it.
It seems strange, also, that it was pointed out throughout the series that people (soldiers usually too, if you think about Journey Blue and the Mummy, not to mention the focus on Danny's previous occupation) appeared in the Nethersphere when they died, if the Master/Mistress was going to take everyday people out of their graves.
I'm happy to be proven wrong on Saturday, and will apologise if so, but I think with Steven Moffat you can be lulled into taking the simple route (and on the other hand, some of his stories and the symbolism therein lead you to over-think too!)