Those are a lot of numbers to digest, brother. I'm a big fan of sports reference, btw.
Lets just focus on Johnny and Robert, here are the stats for their Heisman years:
RG3 2011 - 13 games, 699 rushing yds, 4293 passing yds, 8.59 yds/play, 384 yds/gm, 37 passing TD, 6 int,10 rushing td, 189 passing rating
Manziel 2012-12 games, 1181 rush yds, 3419. passing yd, 7.88 yds/play, 383 yds/gm, 24 passing TD, 8 int, 19 rushing td, 155 passing rating
Certain stats can be deceptive, obviously. They both put up crazy numbers.
I think comparing the schedules can tell what kind of season's they had as well:
Griffin: http://espn.go.com/college-football/...1/baylor-bears
Manziel: http://espn.go.com/college-football/...2/texas-aggies
If you look at Manziel, his first game was against one of the best defenses in the country (was also his first ever start), and that was one of his only two loses (the other one being to arguably the best defense). His team won every other game, and the loses they had, they still had a chance to win late.
If you look at Griffin's, he already had 2 years experience (not counting the year he was injured), and his team had three loses overall, including two blowouts.
Both guys had identical records against ranked opponents (3-2). Manziel also had the win over the #1 team in the nation, I would give him the nod as having the better year. Regardless, I think his next year will be better.
If you would want to argue Cam having the better year, I really wouldn't be against it. But I would still consider Manziel as being the better prospect coming into his first year to the NFL opposed to Cam when he came out.