It was a wise move and was well deserved.
I'm aware that there are a significant number of Vikings fans who are not Frazier's biggest fans (or fans at all). With that said, you cannot deny what was achieved last season, nor can you really say that it wasn't deserving of a chance to finish things out.
First of all, it's not a huge extension like the one the Detroit Lions gave to their head coach—it's two years (ends after 2014).
Secondly, while Frazier's overall record isn't impressive (13-19 in two full seasons, 16-22 including his interim gig replacing Brad Childress), what he did last year was.
Without Percy Harvin for half a year, with a struggling quarterback and a defense that was streaky, Frazier rode Adrian Peterson to a playoff slot in a year where most thought an 8-8 season was the absolute best they'd do.
Also, you're talking about a guy who did this with a team that, frankly, was on the precipice of disaster post-Childress.
Like him or hate him, Frazier became a leader for this team when it really needed one. He centered the locker room and set about the unenviable task of rebuilding the franchise.
A job which, 10-win season and playoff appearance aside, is not done. We all know it—this team can compete but is by no means a perfect powerhouse.
I've never been one to totally buy into the "lame-duck coach" thing for every coach in the last year of their contract. While not having a contract extension could have been a distraction in 2013, it's not a big issue if they're winning. No player is looking at a coach on the last year of his contract who is winning and thinking, "Wow, I'd listen to him...but without a contract extension, hell no."
Was extending Frazier the right move?
If you lose a team, a contract extension won't do much to stop it. Having a contract won't keep you from losing a team anymore than not having one will cause you to lose it.
With that said, in Frazier's case, a vote of confidence from the front office was warranted and says, "Hey, this guy is doing well, we're behind him." It says they believe in what he (with help from GM Rick Spielman, of course) is building and he deserves a chance to finish what he started.
Can this all go sour? Sure, it can even happen this year.
But the financial risk is minimal in giving a guy who has made some real progress getting this franchise back on track some more time to finish the job.