Are you asking about using 2 separate 2x12s? I wouldn't do that. How is it less to lug? That's easily an extra trip to the car over just a single 4x12, plus there is something about speakers interacting with each other in the 4x12 enclosure that works better.
A single 2x12 though can be a good substitute to a 4x12 if you're looking to downsize and get the right cabinet.