One of the most dominant athletes ever. Sadly, I think he's regressed and not just because he's getting older. I never understood a lot of his 'soul searching' on the golf course. Guy wins a boatload of Grand slams and then radically overhauls his swing....fires multiple coaches etc. All this to 'try and get better.' He was living in the 'zone' and should have worked extremely hard to stay there. Instead, he ripped his swing down and changed it....twice.
All the other stuff (women) and alleged stuff (PED's) are potential contributors. Injuries too....though he still seems a 'cut' above the majority of golfers in terms of his physical shape. I recently heard him commenting on how his swing speed is 'way up' again. This, to me, is evidence that he is ok physically.
He just seems to (dare I say) crumble early and often in tournaments now. Part of this is because he was so ridiculously good that the bar is 'too high.' As a poster said above, he was PGA tour player of the year two years ago. That said....it's been an eternity (based on Tiger's own criteria) since he's won a major.