No, he's not too big. Mancini would beat the shit outta Garcia. Mancini would have slaughtered Khan as well. He would have walked right through A Mere and hammered him.
Mancini was strong as a bull, and was a very good in-fighter vs the worst in-fighter of all time with the chin of Will Smith's daughter.
Mancini is pretty underrated. I know he is half Italian so I am accused of bias, but he was competitive with one of the greatest fighters ever, in Alexis Arguello. Yeah he got stopped but it was a good fight.He was a solid fighter. He'd beat these new age slap leap boxercizers into bolivia.
Mancini also pushed Jose Luis Ramirez, one of the strongest and toughest lightweights of the decade, around and basically won a landslide decision. It's one thing to use incredible speed to beat Ramirez at long range the way Camacho did, or use speed and angles at close range like Whitaker did, but to beat Ramirez by going right at him is seriously impressive. Even Chavez backed off a bit and boxed Ramirez, Mancini was vulnerable to quick-handed, straight counterpunchers... that's why he had such trouble with Bramble... but he was as strong as a bull, he was relentless, he had bucketloads of courage and he could pound the body. Mancini was a good fighter. If he was at all overrated during his heyday, with all of the press he got and being a media darling and all of that jive, he's underrated as a result of it now.