McCain wasn't always (or often, IMO) right, and he certainly wasn't a brilliant campaign tactician (Sarah Palin as VP candidate?). At the end of the day, simply being a Republican in Arizona likely had a lot to do with his ability to maintain such a lengthy tenure.
He WAS, among even his opponents, widely respected as a co-worker, public servant, and subject of not always flattering journalism. He was also self-aware and knew he wasn't close to perfect. I believe humility like McCain's is among the traits most sorely lacking in Congress today. Congress cannot represent a diverse society in the binary mode they've adopted.
Regardless of what I think of McCain's politics (as if anyone cared), he was a true war hero. He had an opportunity to leave a North Vietnamese POW camp several years earlier than he did, but he refused to leave without his fellow POWs. For those of you who are bashing McCain because he was a Trump critic, that's what the "loyalty" your guy demands but never delivers is supposed to look like. Your guy would have been out of that prison camp and in a Saigon whorehouse before they finished making him the offer.
I wonder what you guys would be saying today if Hillary had won. My guess is there would be a lot more praise for a man who upheld Republican ideals for decades than what we've seen. Just a guess.