Skarmory pretty much outclasses Steelix in every way, but since you don't wan't to, how about Bronzong instead? He isn't weak to fighting, gives you a ground resistance (or fire if you want). You can use him for support, I noticed you don't have any stealth rocks, or you could try a choice band/choice specs set. Max HP and max Atk or SpA. Those actually worked pretty well for me, it catches everyone by surprise because they don't expect him to be hitting so hard. Steelix just doesn't look like it's doing much for you since you already have Ferrothorn.
You also complain about rain, so why not try fitting Empoleon in somewhere? He stops pretty much every swift swimmer out there and can get a boost from rain too. You might even want to run rain dance on it yourself, to give your team a fire resistance.
Diamond Fc: 0258-9865-0389