I'd rather not press a button for 1 GCD and get quicker fury than spend 3x that time pressing a single button. See that's what we call options in play style, the thing good talents offer. Claiming it's a bad just because you don't aren't interested playing like that it is just wrong. You could extend this same thing to momentum, some people don't want to dash around the fight constantly but it's a good design because it offers variance.
Not everyone likes to be GCD locked. It's fine as long as alternatives are viable.
I think it will be fine to play (fun wise) in legion with extra buttons to press (artifact, talents). Right now, the already dull rotation becomes even worse, so i don't bother using it.
Also, do a Demon Blades specced DH watch out for autoattack timer swings or not? There were so much changes, i lost a track