...you can't win a fight with no gameplan and it seems to me that Briggs just switched up his gameplan and I think it's an extremely bad idea this close to the fight to do that.

Briggs probably just wanted to hear someone say "You have the power to go for the KO right off the bat...don't use the jab, don't set anything up just swing for the fences!" and that's probably the exact opposite of what Mayweather would tell him...he'd probably say "Use the jab, counter when possible and rely on your defense because you want your power to last the full fight because Sergei can take a punch"