Actually the Wrath is very different from the O3 in many ways. First off, the heart of the gun is different. The Wrath's control valve and solenoid is based off the O2, not the O3. Read here:
The regulators are also re-worked in signficant ways, especially the input regulator. There's the jump from reflective to beambreak eyes, of course, as well as a notably different body style that is shorter and more "timmy-like" than the O3, and the Wrath has a dovetail bottomline rail built into the gripframe. The Wrath also gets rid of the O3s weird quirks like the regulator being the bottomline and the O3's pushbutton-release bolt.
You can't blame Diablo for for ripping off Odyssey since the Taiwanese company approached THEM with the prototype and asked them if they wanted to distribute them. It wasn't Odyssey's design or product to begin with. Besides, all these companies are deeply inter-connected through NPBS anyway, so the money is going to the same people. Remember, Diablo already sells TSA loaders made by Odyssey.