|At the end, when we see this other incarnation of The Doctor, did you notice how he was dressed?|
Is it just me or is he wearing Paul McGann's clothes?
If that is the case good GOD is that a clusterfuck of a revelation!?
It could mean that this, and not Eccleston, was the Doctor who took part in the Time War. Which is important in its own right, but think further...
If that is where this new Doctor fits into the Doctor's timelinen it means that Eccleston was not the 9th Doctor, but the 10th. Tennant the 11th not 10th. Matt Smith the 12th and not 11th.
Why is that important? Well, we all know what happens to Timelords when they hit their 13th regeneration... :)