With Dw your still getting one more attack for the most part straight through levels. Until someone starts getting 3 attacks, yet still if your DW'ing it up with say a fighter. You'll still get 3 primary attacks, and one from your bonus action.
Now DW can actually hurt most subclasses, especially those that use their bonus actions for other things. Where as 2h you can use that bonus action as you need it, and at times it's far more effecient to use your bonus action for a subclass skill, then to use it to attack.
Over all it depends upon your build, do you want to do an attack, or do you want to use your bonus action.
i'm not going to analyze it all in depth, means I'd have to pick up a book, which is upstairs.
