Glory is a speedster. We see glimpses of this, especially in her pursuit of Dawn and Buffy.
Glory can't brain suck Spike, and I doubt she'd be able to get the Hulk to stand still to suck his brain even if she could suck his gamma soaked noggin. She might be able to brain suck Banner. We know the conditions of Banner's transformation into the Hulk influences the Hulk's intelligence and stability. A brain sucked Banner might result in a completely out of control Hulk, which Glory, being incredibly arrogant, will probably underestimate at first. A completely out of control Hulk determined to beat her to a pulp won't be as intelligent an adversary, but subtlety and strategy aren't really part of his toolkit to begin with.
The Hulk's transformation heals a LOT of damage. Could it restore a brain sucked Banner? If so, would this "Create a hole," the way it did when Willow restored Tara's mind?