Glory to Rome!
"Let each man pass his days in that wherein his skill is greatest" Propertius Sextus
Doesn't this just reduce the Merlin pool by 1? Seems a bit of a swizz for the good guys!
That's why the suggestion is for only large groups. However, too big a group (10 players) and you never need to put either of the Lances on a mission, since you can get a clean team without either of them. It's like playing an 8 player game with 2 extra voters.