My reply went like this:
"When Tennant was shot by the Dalek in The Stolen Earth, he should have fully regenerated, but instead they wrote in a "cheat" to allow Tennant to stay and add a great part to the story-line. (Not that I disagree with keeping Tennant around, it is just the rules - you take a fatal wound, you regenerate). So I agree that it should count as a regeneration.
Actually, if you think about it, Smith should have already regenerated into Capaldi when he died from the poison from the Joshua tree via the kiss from River. Yes, River transferred the energy to him, but again, he was dead, so he should have gone through a regeneration cycle. He started to change in the Impossible Astronaut, but later on changed that outcome.
From what I understand of the lore, Rassilon put the 12 regeneration limit to keep things in check. So is it really a hard limit?
I'm still trying to figure out if I am now Cosplaying 9 or 10 as the Eccleston Doctor? What about the numbering scheme? I say we just call the Hurt Doctor "W" instead of a number. W for Warrior."
(My last sentence had nothing to do with the rest of the conversation, but I add it for completeness)
In the 50th, we get a brief introduction to Peter Capaldi's (the 12th? Doctor's) eyes. This is during the climax of the show, after two of my favorite quotes by the Gallifreyan General: "Dear God three of them...all my worst nightmares at once." Which is soon followed by: "I didn't know when I was well off, all twelve of them." To which the 12th Doctor replies: "No Sir, all thirteen!"
So, with the regeneration of the meta-crisis Doctor, actually makes him the 13th regeneration per Moffat's counting, 14 by mine (one from River).
So, how could this all work out?
The Parting of The Ways.
The 9th Doctor absorbs the Time Vortex from the "Bad Wolf" Rose and holds it for a few seconds before releasing it back into the TARDIS. The 10th doctor in Utopia stated: "if a Time Lord were to absorb the time vortex, he would become a 'vengeful god'."
The 10th Doctor in the same episode also stated that Captain Jack Harkness was now a fixed point in Time because Rose didn't know how to control the power inside her.
So 9 had the power of a god for a few seconds - and as a Time Lord he would know how to control it. A few seconds is an ETERNITY to an omnipotent being who knew how to control the power. The 9th Doctor could have changed anything in the entire universe and all of time while he held it inside.
What could he change in that time? Anything. It can explain anything. Including unlimited regenerations.
Just something to think about....
We also find out that the Doctor was "9" for about 100 years before he met Rose, as "W" was 800 years old according to his statement in the 50th Anniversary.