Iād go as far as to say this is the best final line. Even the great ones, āIāll always remember when the Dr was meā or āMoment has been preparedā are good, but it feels like any Doctor could say them.
āTag youāre itā feels like only Jodieās Doctor could say it. Just perfect!
'The Power of the Doctor' is the 2nd best regeneration story of the revival ('Parting of the Ways' is, of course, the best).
But "Doctor Whoever-I'm-About-To-Be....Tag, you're it!" is such an all-timer final line. Brilliant closing moment, ironically changed during the edit.