I remember in the primaries leading up to the 2000 election, I found Bill Bradley and John McCain as infinitely more interesting than Gore and Bush. Bradley was a bit more liberal, but McCain just seemed less... Republican status quo. Over the years, I can't say that I was happy with his policy positions as a senator, and picking Sarah Palin as a running mate was bowing to the gradual hijacking of the GOP, but he was usually able to be a respectful human being and assume morally decent positions. He wouldn't accept the Obama birther nonsense, he was against torture, he could be a war hero but call out wasteful defense spending and mostly came on the right side of immigration. He was entirely too aligned with his party on most other issues though.
I think that the reason people liked McCain, even his opponents, is that he was a decent person. His party has been hijacked by people who are not decent, and who feed on fear and hate. I'm not saying that McCain wasn't a party to this (at the very least he was too frequently silent about it), but I'm always drawn to the moment where he shut down the birther woman in a town hall and expressed respect for Obama as a person. I feel like you won't get that from a lot of sitting Republicans right now.
I do hope that people in his party can honor his memory by trying to be more like him. I might not agree on policy, but politicians don't need to be assholes to each other, the press or the public.