I heard two conflicting rumours.  the first rumour is the one we want to be true, that WWE officials finally feel it's Benoit's time for a title run, and since Triple H is going away to Hollywood, they felt he would be the perfect replacement.
But the other rumour I've heard is very negative.  Apparently, Triple H and Shawn Michaels ego's have gotten to a stalemate, so neither one will job to the other.  So Triple H wants Benoit brought in for two reasons.  Firstly, since he is such a great wrestler, he will be able to make Triple H look good in the ring.  Secondly, he'll be a guy who Triple H can consistently beat and never lose to while Shawn Michaels is allowed to look strong as the top face on Raw.