Tyson Jackson will forever get flack for his draft position. Had he not gone 3rd overall in the 2009 draft, he'd probably be known as the player he is: an above-average run stopper who can help your team win. For Chiefs fans, his lack of sacks tells the entire story. Interesting. You didn't honestly think a guy who ran a 4.94 forty would rack up sacks, did you?
Look, Jackson won't ever be a good pass rusher in the NFL. He had 8.5 sacks as a sophomore in college, then his yearly sack total didn't exceed 4.5 in his junior/senior years. But he doesn't pretend to be a dominant pass rusher. It's not like he cast some magical spell, forcing the Chiefs to waste their premier draft status on him almost five years ago. He is who he is, like Popeye.
As I'm sure you've heard, Jackson had a +15.5 rating against the run in 2013, top ten among 3-4 defensive ends. If the Falcons really are planning to run more 3-4 sets, they've effectively locked down one of the best in the business. Sure, his price tag is a little disconcerting, but when you rate -70.6 (25th in the league) against the run, drastic action is appropriate.
I know you all want to see the Falcons sack opposing quarterbacks. Sacks are great. A sack is maybe the single most fulfilling outcome of any football play. But take a step back, realize that a drastically improved run defense will have an enormous ripple effect. Opposing offenses will, out of necessity, become one dimensional, at least more than they have been.
The only legitimate concern about Jackson is his contract. With a cap hit less than $4 million this and next year, it doesn't worry me much. Obviously the Falcons are fine with it. Certainly if his presence doesn't markedly improve our run game, that changes. But I wouldn't bet against him. And neither should you.