I've often wondered the same thing. I've got a one peice base on my 700, and what I don't like is that it prevents me from using the scope as a comfortable carry handle as I do with my Rugers.
I've never had any issues with my 2 peice bases, after years of hard use, and have often considered changing my 700. I think as long as each base is provided with two mounting screws there should be no problem.
"We're all dummies, just in different ways." Old Okie Philosopher