If Arnold were competing now, I don't think he would be Mr. I. I think he be a 300+ pound guy with a wide waist. Freaky yes, but aesthetically he would look like Gunter.
Arnold looked best at his lighter weight, when start to add weight, one's flaws start to become more apparent. Like Flex, he didn't have a wide back or lat spread, so when he got bigger the added weight accentuated that flaw.