I don't doubt the 330 Dakota being a fine cartridge in the field, but no .338 magnum is considered anything else but a fine cartridge. From the Win to the Wby to the Ultra Mag, all offer extreme ranging and hit game hard.
The beauty of the 338 Win is that it is common, can be carried in a lighter rifle (24-inch barrel) as compared to the long action 338s (26" barrel) and is typically a very accurate cartridge out of just about any rifle.
While the Dakota is on a standarrd long action, just as the 338 Win is, it does not offer enough in the way of performance, IMO, to justify the conversion to a soley proprietary chamber.
In the end, typically you get 100 fps velocity out of the Dakota and it shoots less than 1'" flatter over 300 yards and delivers roughly 175 ft-lbs more of energy. Hardly a difference under field conditions. If you wish to push the limits of the .338 bore and truely exceed the 338 Win, you will have to step up to the Ultra Mag, 338-378 Wby, or the Lapua.
