What if Steelix had recieved the ability Dry skin from Dream world?
It's kind of like how I brought up Dry Skin Escavalier before (Escavalier makes a lot more sense flavor-wise :p)
The thing about Escavalier though, is that he is best used to take down Special attackers based on typing/movepool (Scizor too, wishes he had more Special bulk than physical), and has the stats to be an incredible Special defensive threat.
Similarly, with the addition of Dry Skin, Steelix too would have an incredibly good typing for Special walling. Immune to Electric and Water, Resistant to Flying (hurricane), Dragon (D. Meteor), Ghost, Psychic, and neutral to Ice and Grass. Rain would even go a long way to covering up its Fire weak.
The problem with Steelix though (in DPP/BW at least), has always been trying to figure out how to leverage its awesome 200 DEF-- because it's weak to Fighting and Ground, the two attacking types found on almost every physical attacker. Throw in a Water-type weak, and now it's weak to not almost, but EVERY physical attacker. Getting rid of said Water-weak helps because it makes Gyarados (and DD Kingdra) completely walled. It DOESN'T answer the issue with the 90%+ physical threats packing Fighting/Ground attacks for coverage.
Dry Skin doesn't make Steelix much more reliable as a physical wall, which is a problem. However, without a water weak, Steelix has the stats to go for a mixed wall set-- it's special defensive typing is just that good. It's stats do kind of let it down...
252 SpA Choice Specs Jolteon Hidden Power Ice vs. 252 HP / 252+ SpD Steelix: 96-113 (27.11 - 31.92%) -- possible 4HKO
252 SpA Life Orb Tornadus Grass Knot (120 BP) vs. 252 HP / 252+ SpD Steelix: 156-185 (44.06 - 52.25%) -- guaranteed 3HKO
0 Atk Life Orb Tornadus Superpower vs. 252 HP / 4 Def Steelix: 138-164 (38.98 - 46.32%) -- guaranteed 3HKO
252 SpA Life Orb Tornadus Hurricane vs. 252 HP / 252+ SpD Steelix: 117-138 (33.05 - 38.98%) -- 9.25% chance to 3HKO
252+ SpA Choice Specs Politoed Ice Beam vs. 252 HP / 252+ SpD Steelix: 124-147 (35.02 - 41.52%) -- 79.32% chance to 3HKO
0 SpA Celebi Giga Drain vs. 252 HP / 252+ SpD Steelix: 76-91 (21.46 - 25.7%) -- possible 5HKO
252 SpA Keldeo Secret Sword vs. 252 HP / 4 Def Steelix: 152-180 (42.93 - 50.84%) -- guaranteed 3HKO
And let's not forget that Steelix says a big FUCK YOU to Rotom-W and CM Jirachi.
But those Special Defensive stats...
252 SpA Life Orb Tornadus Grass Knot (120 BP) vs. 252 HP / 252+ SpD Steelix: 156-185 (44.06 - 52.25%) -- guaranteed 3HKO
252 SpA Choice Specs Latios Draco Meteor vs. 252 HP / 252+ SpD Steelix: 161-190 (45.48 - 53.67%) -- 2.34% chance to 2HKO
252+ SpA Choice Specs Politoed Focus Blast vs. 252 HP / 252+ SpD Steelix: 316-372 (89.26 - 105.08%) -- 31.25% chance to OHKO
252+ SpA Life Orb Celebi Leaf Storm vs. 252 HP / 252+ SpD Steelix: 255-302 (72.03 - 85.31%) -- guaranteed 2HKO
Hm...... :S
And let's not forget that it isn't just physical attackers who can use Ground / Fighting coverage
252+ SpA Life Orb Kyurem-B Earth Power vs. 252 HP / 252+ SpD Steelix: 250-296 (70.62 - 83.61%) -- guaranteed 2HKO
252 SpA Alakazam Focus Blast vs. 252 HP / 252+ SpD Steelix: 254-300 (71.75 - 84.74%) -- guaranteed 2HKO
252 SpA Life Orb Alakazam Focus Blast vs. 252 HP / 252+ SpD Steelix: 330-390 (93.22 - 110.16%) -- 62.5% chance to OHKO
252 SpA Gengar Focus Blast vs. 252 HP / 252+ SpD Steelix: 248-292 (70.05 - 82.48%) -- guaranteed 2HKO
252+ SpA Life Orb Reuniclus Focus Blast vs. 252 HP / 252+ SpD Steelix: 341-403 (96.32 - 113.84%) -- 81.25% chance to OHKO