Don't know what made me think to make this comparison, but...just for grins, let's go to the tale of the tape:
51 carries, 375 yards (4 TDs)
80 catches, 1055 yards (9 TDs)
43 kick returns, 24.2 avg (1 TD)
25 punt returns, 12.3 avg (2 TDs)
So Howard averaged more yards per catch, albeit on fewer catches (and, to be fair, in fewer games), and more yards per kick return. Combining his '90 and '91 numbers, he averaged about the same yards per punt return. Most impressively, though, Howard scored 12 TDs in 91 touches in 1990 (1 TD per 7.6 touches) and 21 TDs in 108 touches (1 TD per 5.1 touches) in his 1991 Heisman campaign. To have a legit shot at the Heisman, Maclin will probably need to improve on his 1 TD per 12.1 touches average (16 TDs total in 194 touches) and, honestly...he probably needs fewer touches. Over 14 games, 194 touches (13.9 per game) is a ridiculous number. Howard only averaged 9.0 per game his Heisman year, and he obviously didn't wear down much. Maclin was limping from halfway point of the season on.
Anyway, just thought I'd throw that out there.
UPDATE (and Point of Clarification): Anybody who's played NCAA 09 and lost Maclin to injury knows that, at 13.9 touches per game, the injury risk on Maclin is somewhere between moderate and relatively high. He hurt his ankle pretty badly against ATM (reaggravating an earlier tweak, I believe), and though it was to his credit that he still made big play after big play, I think the best-case scenario for Mizzou this year is that other major threats emerge (Derrick Washington, I'm looking in your direction) and Maclin doesn't need to touch the ball 14 times a game. Get that down to the 9-12 range, limit his injury potential a smidge, and he's more likely to a) have better per-touch averages (which does, I think, make at least a little bit of difference...especially for WR/KR/PR types) and more importantly, b) be making the big-time plays late in the season that get Heisman voters' attention. Maybe that's a stretch, maybe not. And at the same time, Maclin's a bit bigger than Howard (6'1/200 vs 5'10/185), and that suggests he could possibly take at least a little more beating without wearing down, so hey...who knows...