I would say Arnold is obviously more influential, but I can't think of anyone that has had the same influence besides Zyzz has had on pushing the whole fitness crusade.
Zyzz basically created the push for the return to "Aesthetics" and the creation of Men's Physique category that has increased participation at bbing shows by a ton.
Look at any Zyzz video and how many people he inspired to workout. Can even Phil Heath say he has had the same effect?
Zyzz basically created an entire culture in eastern Australia centered around health, fitness, and getting shredded for musical festivals. The only other person that is a cultural icon relating to bodybuilding is Arnold.
I know Zyzz gets a lot of hate, but he really did affect bodybuilding in a lot of ways.