All the characters you've listed have shown development. They've grown as characters.
Grey Gargoyle hasn't. His motivation has remained weak and dated, and sans a revamp his power isn't that impressive. After 10 years of being around, people ought to know not to allow Gargoyle to touch them, and to fight him at a distance. It's not rocket science.
The rookies today ought to at least be on the level of Iron Man, Thor et all when they all started out. That's the level Gargoyle's stayed on and without a hook, will stay on.
....if Marvel can take the time to update/revitalize their heroes, then they can do the same to their villains. I'm sure, under the right writer, the Grey Gargoyle can come up with brilliant ideas to use his power in some new way that will take the heros off-guard. But then, most Marvel writers don't bother with charcters like the Grey Gargoyle, unless they are used as cannon fodder (unless it's their golden boys like Hydra, the Wrecker and his Wrecking Crew, Mr. Hyde, and the Rhino).