I got to be honest, I am confused about the Great Intelligence. Just going by material from this season it would seem the Great Intelligence is still alive in 2013, even though here he and his Whisper Men seem to be from 1893. Does the Great Intelligence have time travel capability? I guess he must in order to get to Trenzalore, and all he'd need is to steal a vortex manipulator from a Time Agent who shows up any time between the ninteenth century and today.
I was wondering about this - The GI wants to disrupt the Doctor's time-steam so he travels to Trenzalore to do so but the implication is that he can already travel in time... so it becomes like Baron Münchhausen who's solution to get out of a hole he has fallen in is to go home to get a ladder...