I always thought Ali was a tremendous fighter, and was overmatched by his mouth, and he let it get away from him on many occasions.
His greatest mistake was thinking that nobody was watching when Joe Frazier knocked him backward over his heels in one of their fights and he attributed it to "stumbling"... Frazier hit him so hard it made him straighten his legs until his knees locked, and then he fell backward over his heels, but he "stumbled"...
When he first started "snapping" his punches, he was training in TKD with Jhoon Rhee. The story was told, but unverified, that at one workout, Ali knocked Rhee out, and left for the dressing room. When he came to, Rhee followed him and called him back, and told him "Class not over", and proceeded to knock him out during the TKD class.
As for Ali's style of boxing, I think he pared it down to whoever his opponent was, and changed it accordingly. "Stand up" fighters that stayed in one place got the "dance"; those that were "bob and weave" type, got the straight in advance and retreat; those that moved around got hemmed up in the corners, so he took away whatever their strongest weapon was, and used his mouth to not only intimidate the fighters, but to make the public see something other than a fighter out there... it was either a hero or a pariah, depending on whether or not you liked him.
Here's a picture of Ali...
