A good novel tells us the truth about its hero; but a bad novel tells us the truth about its author.
Simply put, it's difficult to imagine any Doctor other than (Colin) Baker's
in this situation to begin with. It's telling that throughout the trial the Doctor's sole defense tends to be to yell about the injustice of it all
. He never actually goes about saying any of the sensible things like 'you do realize that if I hadn't gone to Ravalox we'd probably all be dead' ...Instead he just blusters on about the Matrix being tampered with (on the quite tentative grounds
that he wouldn't do that) and objects to the entire idea of his being on trial. His reaction is defined by is egotism, and this sort of egotism is a trait unique to Baker's Doctor.
The cliche is that Baker's Doctor is in many ways a self-portrait
of John Nathan-Turner
. This is, I think, a bit strong, but there's a strong sense in which, in 'Trial', he's an inadvertent stand-in for the series itself. Conceived in the afterglow of Longleat
, he is a fatally flawed idea too arrogant to admit to the possibility of his failings even enough to defend himself. That only Baker's Doctor could be in this story is, in some sense, the point.