Its been since 1990 since Gray Hulk was THE dominant Hulk persona. He's appeared a few times since but not ever as THE only Hulk persona iirc. Mightbe some nostalgia but that Hulk when I began my collecting comics 30 yrs ago. So would love to see him get his shine again.
Also he could have his lower base strength or be the same as Green Hulk. I dont have a pref on that.
I think that Gray hulk is also A hard incarnation to get exactly right. Every time he is shown previously he's always been depicted as "Joe Fixit" when that was always an alias that he used, nothing more. Portraying the character as only a thug limits the storytelling potential, at least in my opinion. It's the same problem as always betraying the Savage Hulk as "Hulk smash" and little else.
I think the time for the grey hulk be the dominant personality has passed. I'm not against his return at all, maybe for like an arc or two, but I don't know if he could work on a full-time basis, like he did when PAD was writing him.
But who knows, maybe if they got a really good writer to reinvigorate the gray Hulk and take them on new adventures instead of just always having him fight in Las Vegas, it could be really interesting.