Just finished my second playthrough of patch 6, with my signature dwarven two weapon fighter. At lower levels, it is what it is, a low probability to hit with either weapon, not just offhand. Normally, I'll use a great sword, like Everburn, until I get to 4th level when I can take Dual wielder. Him wielding both named warhammers, or even putting Minthara's in his offhand was quite effective.