The questions

“[...] kickass Peter Dinklage [...] that doesn't make the issue go away but if you want people to be fair and open to what the problem is, you also have to be fair and open to what caused it...” {and more}

it's practically a cliche to make fun of the Star Wars prequels

we all know they suck when compared to the original trilogy

the nostalgia critic agree with that 

but hear him out:

How are Samurai Films Responsible for Star Wars?!? 

(by classicwhovianproblems but with modifications)

I think the fact that the doctor just barely scraped through with fifty one percent at the second attempt at "the academy". 

might be how Romana could do something the doctor and seemingly now other has been able to before "on screen"

and the fact that the doctor didn't seem that surprised by Romana being able to choice by well during her regeneration, in fact encouraging her to chance.

The way I see it is, it's "just" a highly complicated ability that not all time lords can do, at least not many more than the triple first graduates students.

I also think I remember River seemed to be able to decide one part of her regeneration and so did Professor Yana (the Master) when becoming Saxon (the Master).