There aren't a lot of comps for a player like Matt Kemp—at least, unless you're willing to look at previous Los Angeles Dodgers who had outstanding contract years after coming up relatively early and failing to improve on their debuts. It's strange—Kemp has been better than Beltre was prior to his particular 10 WAR season, but his career year came on both sides of the ball. Beltre's story's been told enough times on the sabermetric internet by now—an erstwhile bust made good by his still-stellar defense and a contract that rapidly became a relative bargain.
But Kemp doesn't have any true, obvious talent to fall back on—his solid-to-excellent offense got more excellent, and his middling-to-average defense got above-average. And with three extra years the Dodgers have lashed themselves to New Beltre until he's 34, by which time most center fielders not known for their defense are no longer center fielders.
I'm skeptical that $160 million was the only way they were going to lock him down, but I understand the Dodgers' position here—it's something like the one the Cardinals face with Albert Pujols. Signing him after what he did—which was a remarkable season, peak-Jim-Edmonds on offensive—proves the Dodgers are still serious despite an off-field carnival that's been anything but. They won't get a superstar over the life of the contract, which makes this a bad long-term move, but what they've done is sign a superstar.
I'm still on deadline elsewhere—VEB'll be back to its excessively verbose self soon.