No, because the excelling in the DPS side is their multiplicative synergy effects; the deficiency in the PLD/WHM is on the design side of a tank with a poor gameplay loop and poor skillset for the raid design (and, realistically, even a Physical heavy one doesn't really make them any better) and WHM existing as a throughput healer in a game where throughput is rarely the issue.
MNK, BLM, and SMN pale in comparison to the benefits provided of the others; PLD/WHM have drawbacks because what they want to do doesn't fit the game they're in. My takeaway of fixing tanks / healers is more on the side of readjusting how tanking and healing themselves work in the game rather than fixing the utility provided by the DPS to not be so heavily stacked.
I guess what I'm saying is if they just bandaid new cool shit for tanks / healers as opposed to readjusting how we tank and heal encounters then, yes, I can agree with your point 100%; I just assume they want to readjust what it means to tank and heal in the game a bit more than "Fell Cleave 2: The Cleavening" and hope that's cool with everyone.