Agreed. Not only is Mugabi not in Tiger's class, but his style is taylor made for him. Tiger has regularly chewed up fighters that were just as able and hit at least as hard as Mugabi (ie: Ruben Carter, Florentino Fernandez, Henry Hank). I wouldn't even give Mugabi a puncher's chance here.
Tiger, in his prime, would've dispatched Mugabi a lot easier than a past peak Hagler did. Force against force, but Tiger was stronger, MUCH more experienced against top flight competition, and more durable.
Tiger, by a one sided decision, or ko. He would have been like an iron man against Mugabi, staying in close, unmovable, smothering Mugabi's shots, and pressuring him relentlessly. He would have ground down Mugabi and had him on the deck, much like how he was abl to deck Carter. Tiger was too much man for guys like Mugabi, he'd eat him alive. At middleweight, to beat Tiger, you had to be a "good trombone player" like some boxing scribe wrote in the 60's, meaning that if you boxed and moved and kept a left jab working all the time, then you had a good chance of outboxing Tiger, ala Giardello, Archer and Griffith. No slugger, or power puncher, especially a limited one like John Mugabi was going to beat Dick Tiger, one of the strongest middleweight champi ever.