This isn't a bad article at all. I think Life Herb/Moo MooMilk/Judge should always be in the list in multiples of 4...and I almost think the Quagsire mentioned earlier is an essential.
A few comments though, 1. For the Drifblim guy and the person who asked if it's even been pulled off against him, I had it done to my Steelix in the Georgia Marathon against a LuxChomp deck and lost because of it, haha.
2. And Will, concerning the Gyarados matchup, you do have to factor in an average of 2 Spec. Metals, so average the damage output of Gyarados at 70...unless you play E-Belt...but I think that wouldn't be worth it...since most of the time Gyarados will take a quick prize lead you might get hurt by Blackbelt... Anyway, whether or not Gyarados is doing 90 or 70, Steelix should be doing 120 (perhaps 130 with Skunktank or Crobat G) and discarding the BTS while healing 20 with Blissey and an average of 30-60 with Life Herb and Moo Moo Milk leaving it with somewhere between 10-40 damage on it going into your turn. Gyarados hits for 70-90, Steelix heals off about 60 on average, leaving it with about 30 damage on it...and KO's Gyarados....It really isn't a good matchup at all. I agree with Erik, at the Marathon Steelix was 4-0 vs Gyarados. But dude message me when you're going to the Anderson league again and I'll go to and we can play the matchup for a 2/3 if you want (and we can find a secluded area, I know you're guarding of your G-Dos list, and I don't blame you). But anything can happen, so I'd like to see how the match would go, especially against your unorthodox list. I think your G-Dos would give this article's list a tough match, I'll say that...
3. One more thing I want to add to the general discussion....If a LuxChomp build that does not play Blaziken of Drifblim does not get the donk or an early win due to lack of pokemon on the field for Steelix, it's almost auto win for Steelix...however, vs DialgaChomp...the match is about 70-30 or higher in favor of DialgaChomp
4. Gengar really isn't as easy for Steelix as the article makes it seem. The idea is to place Ruins of Alph in play, drop Skunktank, poison structure, and Gaia Crush (discarding the stadium if you have a ton of trainers in your hand) for the KO. However, Skunktank can get sniped and can be early Hurl into Darkness bait. Crobat helps the matchup tremendously as they rarely see it coming. I was 5-2 vs Gengar in the marathon and EVERY game came down to 1 prize and basically a fainting spell flip at some random point of the game, and in Swiss they all went to the 3rd turn of the +3. VileGar just has too many gimmicks to say it's a 70-30 matchup. Of course if you HAVE to you can retreat (blah) the Steelix and then Psychic Restore with Uxie to avoid fainting spell, since you can just (in theory) energy stream back to Steelix. I'd say it's about 50-50 or maybe 55-45 Steelix.
5. There's no way Machamp is a 50-50. If they don't get the donk, it's about 75-25 in Steelix's favor. Machamp's damage output is too low, I mean you're never going to hit a Machamp with 4 energy on it with Gaia Crush, since you know it's going to rage you back...so you just Energy stream and then Crush...Otherwise it's not hard at all with Crobat and Skunktank to OHKO a SF Machamp, so I don't forsee a Machamp getting enough energy on it anyway. The Champ prime might make a little difference...but even doing 100-120 with Champ Buster will leave Steelix with an average of 60 hp left....then you heal a lot of that damage off (unless you just can't flip heads), and 2HKO the Champ. Even if you DONT flip heads to heal the Steelix...you'll hit the champ for 120 (factoring e belt or a stadium and skunktank after their turn) and if Steelix is KO'd then Psychic restore for the KO... Besides, an e-belted Steelix with a Skunktank G and a Crobat drop will KO a damageless Machamp Prime after their turn (or a blackbelt on Steelix's turn with any combo of the e-belt, skunktank, or crobat shenanigans wil OHKO it before it can even attack the Steelix since Machamp will take a prize lead). Unless of course they run the Seeker Fighting Tag combo...which I haven't personally seen played to any success anyway...
that's just my 2 cents worth tho!