The War Sledge is revealed when you equip it so you advertise the fact that you have a sweeping attack. Your opponent will play accordingly. Personally I just run one copy of Whirling Strike in my book. The opponent never sees it coming and cannot counter it. Plus you can use an actual good weapon such as the Morning Star or my favorite the underrated Staff of the Arcanum.
2 hands occupied for an advertised sweeping effect, a 50% daze chance, and the same damage as every one handed weapon is just not worth it. Granted that is my opinion not necessarily fact.