First is ROGUE no ROUGE.
And no one is saying otherwise.
Although Rogue does much more than just absorb life force, she absorbs life force, powers, emotions, minds, and physical and intellectual abilities. the absorption of life force is a small thing of all that she can do.
And no Gentle does not rival anything with the Hulk, only if he is the weaker version of him and still I doubt with Frenesi and Roberto that they both have better strength merits than Gentle.
And it doesn't change my initial idea. Rogue is currently by far the strongest x-man when it comes to super strength.
Rogue > Apocalypse>>> Roberto (sunspot)> Frenzy> Gentle = Moly> Colossus> Stronguy= Northstar> Monet> Rockslide.