It is a pity that God does not allow us to have an instant replay of alternative election outcomes. For example, in the 2000 election, I thought that it wouldn't be too bad if McCain won the election for President. You remember the election ended up with George W. Bush narrowly beating Al Gore (my favorite) in an election decided by the Supreme Court. Of course, it wasn't to be that McCain would get the Republican nomination.
But let's pretend that McCain won. How different would things have turned out? He voted to go to war in Iraq so that might have been the same, but would he have avoided another financial collapse known as the Great Recession brought on by George W. Bush (Bush-43). He opposed the Bush-43 tax cut in 2001, but, then in 2008, he favored making the tax cuts permanent. In 2013, Warren, McCain, Cantwell, and Angus King proposed to rein in "too big to fail banks" with the 21st Century Glass Steagall Act.* But then he voted against the Dodd-Frank Act.
I find McCain's actions regarding financial institutions to be confusing.** Therefore, I'm not sure he would have avoided the Great Recession. So maybe it is just as well he didn't become president as he avoided my tag that George W. Bush is the worst president ever.
By the 2008 election where McCain did win the Republican Presidential primary, he seemed to have lost a step or two and show some signs of senility. On at least two occasions he complained about Shiite Iran training Sunni insurgents in Iraq whereas the Shiites and Sunni's are dread enemies.
McCain considered himself to be an Episcopalian until 2008 after which he said he was a Baptist.
Though I conclude that it is just as well that McCain didn't become President, I do feel he was a superb Senator. I will miss him dearly.
* https://www.washingtonpost.com/news/wonk/wp/2013/07/12/elizabeth-warren-and-john-mccain-want-glass-steagall-back-should-you/?noredirect=on https://www.cnn.com/2014/07/17/opinion/warren-mccain-big-banks/index.html
** https://search.myway.com/search/GGmain.jhtml