He was better on paper, but they were effectively very similar QBs. Manziel arguably had much better weapon(s) to work with in Evans, Christine Michael, Swope, etc, not to mention a couple first round linemen protecting him. Richardson in comparison at Florida didn't have the same talent, the highest pick in his supporting cast was a 5 star WR in Shorter that went 5th round and has yet to have any stats in the NFL.
There have been lots of QBs to come out of the Big 12 and PAC 12 that were elite studs in college, but they rarely pan out the same way in the NFL because they're not used to playing against good defenses regularly. Caleb Williams, Kyler Murray to some extent, Sam Darnold, Josh Rosen, Marcus Mariota, Robert Griffin to an extent, Brandon Weeden, Sam Bradford, Mark Sanchez, Josh Freeman, Jake Locker, Vince Young, Matt Leinart, and more. All first rounders from the PAC-12 and Big 12 that failed to live up to potential. The only good 1st round players to come out of those conferences? Mahomes, Goff, and despite a short career Andrew Luck. You could put Justin Herbert in there too, he's been good in a short time despite being on a poor team. As much as I like him, Baker hasn't lived up to the hype of being a #1 pick, but I wouldn't say he was a bust and he statistically had his best season ever last year with Tampa.