Antennagate affected a vocal minority. Maps affected basically EVERYONE using an iOS device. On top of that it was a very publicly visible one-to-one comparison between a Google product and an Apple product. To the world, it looked like Apple was faltering, that it couldn't at least match Google's product. That's a much larger PR problem than a hardware design flaw. Steve knew that, and I don't think he would've let Maps out the door in that state. So that's on Tim.
But Maps is fundamentally not an engineering problem, but a data problem. Apple gets the Maps data from 3rd-party sources, and a lot of that data is poor to terrible. You can't just patch that in. Google spent years getting their map data to be excellent, with their mapping cars and ground truth teams. Apple foolishly/arrogantly thought they could just license some data from other companies and match Google Maps in quality. That arrogance probably stems from Forstall, and I have a feeling Cook wasn't down in the weeds enough to know how bad Maps was, let alone understand that they couldn't just cobble together Yelp and Tom Tom data and be done.