I don't know about worst, but Lennox Lewis' is not pleasant to watch. It's like his feet want to move one way, and his body another. I've always thought it odd that Lewis had such great timing, and still appeared so uncoordinated. I guess it was good enough to get the job done, and against a good resume at that.
You could say Trinidad. I mean, the way he always had his back foot up on its heel, it made him have poor balance and led to him getting knocked down a lot. He's not the worst though.
Interesting question when considering prominent names. Among heavyweights, Marciano probably had the slowest feet, but slow feet don't necessarily equate to bad footwork. The Rock stood as though his feet were encased in cement, making him extremely difficult to move back, and giving him a tremendously strong base from which to generate power. Carnera had huge feet, and could hardly be described as fast, yet we don't see him tripping over those feet (even when he twisted his ankle against Max Baer), and he demonstrates respectable mobility. George Foreman cut off the ring very well. Joe Frazier showed good mobility against Stander, and in his rematch with Foreman. Joe also closed very quickly on the attack. Perhaps George Chuvalo could be considered. Floyd Patterson outmaneuvered Chuvalo in the corners, and Floyd wasn't noted for his footwork. Bonavena also used lateral movement to trouble Chuvalo. However, neither was Chuvalo ever decked, demonstrating that he wasn't prone to being caught off balance either, unlike say, Patterson and Danny Lopez. "Flash" Gordon's stereotype that, "All Mexicans have two left feet, with the exception of Miguel Canto," might offer some clues about who else to consider. ("Flash's" stereotyping could be unfortunately indiscriminant though, as he somewhat mindlessly classified Sal Sanchez among those left footed Mexicans. Sal may not have been as fluid on his feet as Wilfredo Gomez, but he was certainly more mobile than Little Red.) Who was least effective at moving away from trouble, was most prone to simply following an opponent around the ring like a dog on a leash (instead of cutting off the ring efficiently), tended to move straight forward and back, seemed most unable to change position in the ring quickly, yet somehow managed to achieve some level of accomplishment despite these deficiencies?
Huh?:huh The Hawk was more than capable of flying around the ring when the situation called for it, and the speed of his reverse gear compared favorably with LaRocca's. He didn't often have occasion to utilize lateral movement, but he was known to do it, and fluidly.
id say oliver mccall for champions, he would absolutely do nothing but come straight in, wheather he is catching punches or be set up for a trap, his best success was when he was forehead with you. danny lopez and alexis arguello i think would be another ones very stiff boxers that seem to reset when thay pivoted, both had trouble with movers and both had the power to overcome fighters that they could not corner by using hard stiff jabs and good right crosses to jam up counter punchers and feinters.