I think the show becomes inherently different with 5 complete strangers. These guys being somewhat acquaintances at least and being part of the same community (English youtubers) raised the chances of the winner not running exponentially. And of course, Mike being a fairly influential youtuber doesn't probably care about 6k as much as a middle-income stranger would've,,(reply>), yup. Also.. him being a Youtuber with a sizeable audience comes with the extra baggage of reputation management. He would absolutely not want a permanent video record of him being a bastard to a group of other fairly agreeable Youtubers that he might also want to collaborate with in the future.