Sure, give the warcleaver bonus against shields and make both the great axe and the great bardiche obsolete, why not?
Warcleaver is pretty well balanced, I'd say. It's cheap, long, reasonably fast, has good damage, no stab and is unbalanced. Sounds fair.
Also, an axe head is a wedge, a cleaver is pretty thin, maybe less than half as thick, and is thus not well suited for splitting wood.