Except that by the time you get the SAW head positioned and verify everything is ready to go you could have two more layers in with FCAW. Plus you lose productivity with flux management with SAW. Something often overlooked and the jist of the OP.
Also, you can't take full advantage of the higher deposition rates on smaller diameters which is the biggest advantage of SAW. You can't crank the amps up too far or your beads hump from being wet while rotated off the back side where gravity is not your friend.
I could see perhaps them being more equal on that diameter if you had impact regimes as a concern. This would limit the amount of metal you can carry with FCAW, and minimize its weave advantage as well. Especially if you were running an electrode extension on SAW. I'd be tempted to use SAW then. Electrode extension technologies have not been perfected for FCAW yet as far as I know.