What does unmodified mean, is it referring to your base melee skill, or your melee skill after dexterity scaling
if it is the former I doubt it is worth a feat given the harsh conditions to activate, if it is the later however It might be one of the strongest feats in the game, either way, it is a must-have for versatility builds that use the dex/melee for their damage
the real question is whether or not it is worth the specialization points