I don't think he's afraid of anything as much as he sees a bad deal.
I wouldn't want to be coaching in the SEC where everything football (particularly recruiting) runs through Tuscaloosa, unless I was professional agitator Lane Kiffin (who got a raw deal at USC). What he was able to do with recruiting out West is hella impressive, but it helped being part of a traditional power in a conference where it was clearly the alpha. That all changes with the conference realignment: now, even if Oklahoma wins the SEC championship game, they're just going to end up playing an over-valued Alabama team in the playoffs anyway. What's more puzzling to me is why Oklahoma would want to leave the Big 12 to be a small fish in the SEC: even if they end up making more money in conference payouts, they lose the kind of control over media allotments they had as the premier team of their previous conference. Should Lincoln build the kind of program he had in UO at USC, he'll have infinitely more control over the program's exposure than he would in the SEC.
Whether coming out to the Pac 12 results in more success for him is hard to say, but he will almost assuredly dominate the conference. Oregon has long since maxed out, and the rest of the conference is full of also-rans (except for maybe David Shaw, who's can make magic out of middling recruiting classes). He even has the benefit of being in the weaker of the two divisions, meaning his best teams can roll to the Pac-12 Championship with relative ease, setting up the opportunity to make a standing invitation to the Rose Bowl. He's got the kind of place here that he would have continued to have in Norman had the move never happened.