Wayne knows enough about bodybuilding to know that is a horrible idea.
They could go the 2005 route, and put out a memo requesting a 15% reduction in overall mass combined with smaller stomachs. Ronnie actually followed this memo and came in at 275 - he was very hard and looked very good, but in hindsight, he took a big risk with over-diuresis, or just over-dieting in general.
Other pros - like Markus Ruhl, looked very bad in 2005, attempting to downsize as per their memo.
There is no "solution" here on the side of the competitors. Change the judging standards, and have it enforced on the judging end. If a certain height to weight ratio is desired, set it, and have an actual weigh-in. Allow judges to penalize pros who go way off the tables with the height to weight ratios.
Make it clear that being over-sized is grounds for losing points in the judging. Beyond that, just make things clear with the judges and enforce it on that end.
Drug testing in bodybuilding? Seriously?

PS - nice to see Arnold wish to drop Jim Manion. Arnold certainly doesn't need him, and probably doesn't like his disrespectful attitude.