Mr Awe wrote:
The problem with having past Doctors appearing is some are too old or too dead.
Some sort of Tribbles mixing old and new futage would work.
Plenty of ways around both obstacles. They could go the Tribbles route.
Or, they wouldn't have to include all of the past Doctors, pick and choose. Some of them appear close enough to be workable. And there's always the Time Crash explanation.
#8 (Paul McGann) could *easily* come back.
And Sylvester McCoy (#7) was wearing *old age make-up* in the TV movie where he regenerated into #8.
And really, we never actually saw #6's face, since the actor, Colin Baker, wasn't in the episode (but Sylvester McCoy in a wig, with his face fx'd out) - so you could just put a *wig* on him, and use your imagination to fudge the extra weight.
#5 and #4 look much older than when they regenerated...but you can come up witha "Time Crash" like technobabble explaination to explain it away, I'm sure.
And many people here have commented on how much the Sean Pertwee, the son of #3 actor John Pertwee, looks and sounds like his father...with the right wig and costume, he could *be* #3!
And the fist two Doctors you could just recast...or use old footage ala' "Trials and Tribbleations" to CGI them in....or use CGI re-creations...or a similar-looking actor with a little CGI and voice help... Or you could just re-cast them like they did for #1 in "The Five Doctors"...