Well, McCain will certainly run, but he faces an uphill battle in the primaries (from the likes of REAL Republicans, like me.)
As far as questions, along with health questions, what about where the man's "center" might be? Why is he so prone to side against conservatives when that might get him some big ink? And, for me, why oh why did he turn his back on and vilify his comrades-in-arms - the Swifties?
Unfortunately, I see some disquieting similarities between McCain and (ugh) Kerry.
McCain is also notorious for having an uneven temper, not a quality you would want in a Commander-in-Chief.