MPLS core networks that use Label Distribution Protocol (LDP) are common in SP core networks and have served us well. So, the thought of pulling the guts out of the core is pretty daunting and invites the question why you would want to perform open-heart surgery on such critical infrastructure.  

This article from Andy Mulheirn attempts to explain the benefits that would accrue from such a move and gives a high-level view of a migration strategy.