"...would it have proven to be a better design..." No. It's not just the poorly made, stamped, op handle that makes late model Universals junkers. Mind you, a buddy of mine had one that never gave him any grief.
Real Carbines, from 10 different makers and hundreds of parts makers, were used in several wars in all kinds of really crappy conditions from salt water, sand and the really, really crappy conditions of Korea and just worked.