Rizzo is so much more polished at the plate and is overall a much better hitter right now than Bryant. It took him several years to get there and he made what appear to be some significant changes in his approach, and I'm not convinced there's a lot of guys out there that could do the same thing. I mean, he was touted as a guy who would likely top out around .280 in avg., and he's well above that right now with no reason to think there's some big regression coming. Rizzo may not have as much WAR, but he's a better player right now and Bryant, who's been a lot better than I expected at 3rd, is getting a decent bump from his position I'd bet (since I'm too lazy to look it up right now). Either way, it's awesome to have them both for the next 6.5 years.