I just checked this claim myself. It is completely inaccurate. For my class (DPS Powertech), I found at least 3 enhancements and 2 mods that were unique to the Campaign set. And this says nothing of the pieces that you can only get as campaign. Can you wiggle them around to get the same numbers? Perhaps, but the fact remains that you do have more flexibility if you can get both BH and campaign.
The enhancements you could get from another classes gear, as for the mods, please let me know what mods they are in campaign that you can't get in black hole. Your post seems completely inaccurate.