I get what your saying. Mages need to bring more utility to a raid. But they've never been a raid utility class. The only fight you HAD to bring a mage to was High King in BC for spellsteal. You brought mages cause they brought damage. Alot of it. In any way you needed it. Burst, sustained or AOE. I personally prefer this style for a mage and let the other classes fill in the raid utility. As far as personal utility in a raid, we have a lot of it.
I would be more on board with your mage table buff if it was the same thing as a healthstone. As you said, in high level raiding a heathstone is extremely useful. No reason to put that on one class when it could easily make sense to add it to a mage table. But with them moving to flex style normal and heroic and 20 man fixed Mythic, the chances of you having a Warlock only go up. I don't see them adding that to mages with their new goals for raiding.