Ok let's compare them
...
Total points: Goodman Zargon: 12-13.5 points vs WotC Zargon: 13 points. Roughly equal, which I find somewhat concerning, when you consider Goodman Zargon is a CR 13 monster, while WotC one is CR 17. I get a sense between being bigger bag of hit points and his regeneration you can only stop by dealing him damage he is resistant to, WotC Zargon will be tedious to fight against, while seven attacks per turn and three with legendary action make Goodman Zargon more of a pain in the bottom area to run. Now, Zargon who combines two statblocks would be an utter horror to fight, that would be a final boss material.