I think takedowns are a little overrated, but why not look at the flip side of the coin? Takedown defense is undervalued. No one likes to see a guy win a fight by lay n pray, but the bottom line is, someone who can take you down multiple times is controlling the fight, and where the fight goes, even if they are not doing much damage. It is imperative that a successful fighter be able to control the fights location, and if he can't, he isn't successful.
Someone like Liddell is a guy who relied a lot on outsriking guys, he was a bit one dimensional, but he was a champion. He got away with it because his takedown defence was really good. (Then people figured out how to outstrike him and he got old fast) Then look at a guy like Houston Alexander. Strong and a very good striker, but his ground game and takedown defence are useless, so the result is, he is virtually a can. Matt Hughes is another good example, he sucked balls at striking, but won the takedown game bigtime, so he was a dominant fighter.
If you can't take someone down, you better be able to stop them from doing it to you, it is probably the single most important aspect of MMA. I hate lay n pray as much as the next guy, but either defend the takedown or lose, it's that simple. If a fighter can't defend it, he's not good enough at a crucial aspect of MMA.