I think the idea came from basically just that, its great defenses, 321HP minimum, Water Absorb, Belly Drum/Hypnosis and Ice/STAB Fighting/Water offer brilliant coverage after Belly Drum. There was also the fact a few agreed and absolutely nobody challenged it hence why I threw it up there.
Steelix- Actual offensive coverage with the elemental fangs a speed modifier, generally great typing, ideal SR'r on top of what we know it already does well. However I do agree it could be considered on basis of its attack seems awfully low.
Actually I put that because although it was suggested there was some very fierce arguments against it early on against it. (Me included).
Lapras is just something that slipped my mind because to be honest it hasn't really been mentioned in the thread.
Ah, well basically I really don;t think Poliwrath should be in BL.
First: The Drummer set isn't horribly viable. If you want to use SubSalac that already takes up two of your moveslots, and Hypnosis would eat up a third, leaving you with Waterfall which a load of UU pokemon can eat and finish off your 25% remaining HP, Brick Break, which is even weaker than Waterfall and also can be stopped by other Bulky Waters.
Even without Hypnosis, Poliwrath suffers from low power attacks. Waterfall is 80, Brick Break is 75, Rock Slide is 75, Ice Punch is 75. Only Earthquake even meets 100 pre-STAB BP. Even then, the only thing EQ is covering is Electrics who by most rights would get owned by Brick Break anyway.
Furthermore, Poliwrath is Belly Drumming off of 85 Base Attack. That isn't bad per se, but with 70 speed to boot it needs to invest nearly all its EVs in Attack and Speed to even think about sweeping, and it is still heavily vulnerable to Choice Scarfers.
Now, my set of preference varies between the max HP Subpuncher with Waterfall and a Bulk Up set with Payback, depending on which tier I'm using it in. The Subpuncher is great because Poliwrath has middling speed and the STAB really makes it a powerhouse.
Either way, I see Poliwrath as a UU Staple. It doesn't unbalance anything, but it is useful in a wide variety of situations. Poliwrath is the pretty much the UU equivalent of Swampert, sans Stealth Rock of course. My personal opinion is that the defensive sets are much more viable than the Drummer, especially now with Focus Sash, Subversal, Choice Scarf, and more priority moves everywhere.
As for Steelix? It was BL last gen, and it got some cool new toys in Stealth Rock and Gyro Ball. It's effectively a differently typed Skarmory, and there are few reasons why anyone would choose Aggron or Probopass (or LOL Bastiodon) over it, seeing as Steelix lacks any 4x weaknesses and takes even Earthquake quite well. UnStabbed Fangs are craptastic without an attack boost, especially on Steelix which devotes most of its EV's to HP. Note that Steelix's "low" attack is equivalent to Poliwrath's.
Ohm and one last note: I've used Choice Scarf Manectric. I wouldn't advise underestimating something with 339 SA that has Tbolt, Hidden Power, and Flamethrower/Overheat readily available. The SubPetaya set never lost any effectiveness either.
Oh, and Luxray pretty much stops Lapras dead. Intimidate ruins the Physical sweeper (LOL btw.) and Luxy can eat a Surf and strike back with a monstrously powerful CB Spark. If it has Rivalry instead of Intimidate, you're in for big pain if you're the same gender.
Last time, drop it. 
