Not quite...
Bottom line is...it's a PHYSIQUE competition, not a dance contest, not a best poser contest.
MONEY motivates athletes for the most part. No one got into it for the money, but once you find yourself there....it's very much part of being a professional BB.
As for the judging...any physique contest is a combination of all you mentioned, so it's not that easy to simply just "judge each round for what it is..."
most muscular might not be the most symmetrical, or proportioned...so Paco Batista wins that one
most symmetrical isn't necessarily the most muscular, or even one of the top physiques on the stage...lets give it to Kenny Jones
best poser isn't necessarily any of the above...lets give it to Melvin.
So, according to what your ideal is...we have three different round winners, which in all probability, makes it impossible for the best OVERALL physique on the stage, to win the physique contest. A guy who maybe doesn't win ANY round.
How about Kenny, who wins the most symmetrical, also wins the posing round...in the words of my friend Meatloaf ...2 out of 3 ain't bad. It also most likely puts him in the top 3.
As Larry suggested, perhaps some weight could be weighed to each round.. (ex. muscularity 50%, symmetry/ proportion 25%, posing 15%, posedown 10%).....but now were right back to where we started, which never worked in the first place.
Should a guy with the best physique lose the contest because he was the worst poser?
Should a guy who ends up with the best score by an average, win the contest despite not really having the best physique?
To answer your last question: What makes this a better system, is it rewards that competitor with the best PHYSIQUE...making it more convoluted, mathematical, etc...only insures more questinable outcomes.