They also said outright that the ethereals will remain 'desirable' even during the new xpac.
And it was pointed out AS SOON as the relic tag was revealed that if ethereal level procs end up being on Relic items the Ethereal will have a distinct advantage in being able to use multiples of them, not to mention you could wear 3 ethereals + 1 relic.
Damage procs dont scale well instantly making them terrible for any decent DPS class. I suppose they could be 'okay' for classes with poor DPS but if they have poor DPS where a proc would make a different they probably have other class roles to worry about. The entire idea of a well performing proc goes against the 'active v. passive' DPS changes being done to auto attack and class damage abilities. AND we were promised procs would be nearly removed outright to help with server performance.
The ways ethereal type procs outpace straight damage ones are numerous.