Yes, quite honestly. It transforms Disney from a creative company to an IP holdings company. Marvel and Star Wars will be extremely profitable for a number of years, but what happens when they aren't? It's not easy to fire up the creative juices to make new areas of profit when they start to peter out. Hell, we've seen that from Disney in the past decades with bungles like TRON: Legacy, Lone Ranger, and John Carter. From a Wall Street perspective, Iger is gold, and he will leave gold. But Wall Street is always looking for increases. I'm not sure the next person can do what Iger did.
There are only so many Marvels and Star Wars's out there. Once that well is dry, they're gonna have to scramble, and I don't know if they can recover from that.