If Tim is in fact picking up on semi-obscure TF facts here, then first of all, he's really impressed me, and second of all, he's wrong! Yes!

For the benefit of no-one here, I shall tell all:

For years, there was a rumour than Orson Welles didn't finish his lines as Unicron, due to the slight inconvenience of his death. The fumour then stated than Leonard Nimoy (playing the role that surely he is most famous for, that of the non-yet-insane Galvatron) finished the lines.

HOWEVER (da da), it has been recently confirmed that Welles did indeed finish all his lines. It was confirmed by, er, someone, who worked on TF:TM. Possibly Susan Blu. Or Judd Nelson (who we love).