I can't stand the argument against Ice Fang because it removes Breloom from the counter list because that notion is ridiculous. And not just because you said that there are better ways to deal with them like U-turn and then say we should disallow U-Turn -.-
0 Atk (custom) Ice Fang vs. 4 HP / 0 Def Breloom: 112-134 (42.74 - 51.14%) -- 51.56% chance to 2HKO after Stealth Rock
We have a 50% chance of 2HKOing Breloom IF CAP5 runs Ice Fang, Breloom switches in on said Ice Fang, Breloom does not run Low Sweep and/or decides to set up OR CAP5 is Lum and Breloom uses Spore. To put it in perspective, that's like saying Offensive Celebi is not a good switch in to Jellicent because Jellicent can 2HKO with Shadow Ball, or that Gliscor doesn't counter Forretress because Forretress can run HP Ice. We might as well take the notion of switching in safely and throw it out the window. Also, Toxic Orb Breloom still beats CAP5 even if it runs Ice Fang. Breloom can still come in on any of CAP5's STAB moves with perfect ease. Malaconda beats Breloom in a vacuum, but in practice the chances of it beating Breloom are slim and you'd have to be insane or desperate to try to do so.
What Ice Fang DOES do is prevent Salamence, Dragonite and Landorus as turning Malaconda into set up bait. Admittedly, there are better non-attacking methods to preventing them from setting up, but we aren't there yet in the discussion and Ice Fang is currently the best way of preventing Malaconda from being a sitting duck against them. And furthermore, "just because we allow Ice Fang doesn't mean it will get it!" As a side note, I don't think having access to a 65 BP Ice Move is opening up a Choice Band set when you have only 55 Speed and 100 Attack. Allow Ice Fang.
I said there are several other ways to deal with the threats we would want Ice Fang for, and U-turn is one of them, even though i didn't like it at the time a made this post. This thread isn't about me, it's about everyone's opinions and since the majority wants U-turn allowed of 'course i will mention it when discussing other ways that Malaconda has to deal with the targets fo Ice Fang.
You are right that i am a bit paranoid about Ice Fang, but i would rather be safe than sorry. Also, if you read my post carefull you will notice that hitting Breloom is not the only reason i don't like Ice Fang. Ice moves offer super effective hits on many dangerous threats in OU, threats that the CAP shouldn't be able to hit so hard. Malaconda can already 2HKO Landorus and Dragon Dancing dragons without Ice Fang, so i don't get why we need a move that nearly OHKOes them after SR. Being able to prevent something from setting up on you and almost OHKOing it after SR are two entirely different things. Malaconda already 2HKOes (with SR) most set-up sweepers that can get past it, and you want to give it a move that almost OHKOes some of the few sweepers that it can already 2HKO with its STABs? Why?
Out of the common setup sweepers in OU (that are not walled by Malaconda), Malaconda can OHKO-2HKO Keldeo, Terrakion, Landorus, Dragonite, Salamence, Thundurus-T, Venusuar, Gyarados, NP Celebi, and Volcarona, with the help of SR, while the only sweepers that it can't are SD Scizor, SD Toxicroak, SD Lucario, and SD Breloom. Try and compare this to other great defensive Pokemon in OU with similar offenses, such as Jirachi and Ferrothorn. Assuming both Pokemon use two attacking moves as Malaconda does (Malaconda will need Rapid Spin + Recovery/Sub/U-turn, which only leaves room for two attacking moves) and not taking into account non attacking moves as Malaconda doesn't have any of them yet, here are the setup sweepers that can setup on them (avoid the 2HKO from attacking moves after SR):
SpD Jirachi: SubCM Jirachi, LumDDnite, SubDD Gyarados, Jolly SD Breloom (it gets a free turn due to Spore), and SD Scizor
Ferrothorn: SubCM Jirachi, SD Breloom (it gets a free turn due to Spore), SD Scizor, SD Lucario, SubCM Latias
As you can see the CAP can OHKO-2HKO with SR more setup sweepers than two of the defensive Pokemon of OU with the best offensive pressence. And you want to give Ice coverage to this Pokemon? Why? So that RP Landorus can't set up a Rock Polish against Malaconda? Every defensive Pokemon has a few setup sweepers that can abuse its pressence and make it a liability, but this doesn't prevent them from being great Pokemon. Malaconda can't be perfect and some sweepers will be able to setup on it, and this is why you have teammates. Let's not forget that one of the goals of the CAP was to help sun teams with their teamslots, combining multiple roles in one slot so they can afford to have a better defensive core. So in the teamslot that Malaconda saved you, use a Pokemon that deals with RP Landorus such as SpD Bronzong, Mamoswine, Latios or whatever you want.
Finally, Malaconda has such a good offensive pressence against setup sweepers with just Power Whip and Payback. We still haven't even started discussing about non attacking moves. Encore, Dragon Tail, and Whirlwind can all prevent Landorus from setting up with Rock Polish without giving you coverage that lets you almost OHKO some of the best sweepers of OU.
tl;dr All defensive Pokemon have some setup sweeprs that can setup against them but this doesn't prevent them from being excellent at what they do (Ferrothorn and SpD Jirachi). Malaconda can also use more ideal ways to deal with Landorus than Ice Fang, such as Dragon Tail, Encore, and Whirlwind, making Ice Fang both unecessary and possibly dangerous for Malaconda.
Technically you are correct in that its Dugtrio actually eliminating Heatran. However, in practise, if we give it U-Turn, then we remove Heatran form the list of mons that threaten / beat Malaconda. If you look at it in a vacuum then yes, 1v1, Heatran would win, however, in an actual battle scenario, Heatran cannot and will not switch in on Malaconda, something that's quite a large problem when its supposed to be a major counter. Label it however you like, the point is U-Turn means Heatran isn't switching in on Malaconda period (heck a case could potentially be argued for Malaconda decreasing Heatrans usage due to Heatran being unable to handle it + the general sun team) since a simple U-Turn to Dugtrio ends it.
To put it really simply (assuming no HP Ground or something)
On PAPER Heatran countered Genesect
In PRACTISE Heatran didn't counter Genesect since the threat of U-Turn ---> Dugtrio was far too high.
Baton Pass sorta mitigates this issue although its worth noting that Heatran would still have to worry about a Baton Pass to Dugtrio, which simply pops the balloon with Reversal and Earthquakes, thus winning unless Heatran has Flame Charge / Choice Scarf / Magma Storm / is shed shell / gets lucky with a burn. You also still beat SDef Heatran or basically any Heatran that runs Leftovers / has the balloon popped. And again, you also beat Ninetales, a mon that was brought up a lot as something people wanted Malaconda to be checked / countered by so w.e
Very good post and i agree with most of it. However, if Dugtrio comes in against Balloon Heatran via Baton Pass Heatran won't be trapped as you imply and thus won't have his Balloon broken by Reversal. Also, while Baton Pass can still allow the Malaconda player to pivot to Dugtrio and trap Heatran on the switch, so can a double switch. If you think something dangerous is coming into Malaconda then by double switching you get the same result with Baton Passing, especially when considering that Malaconda is so slow that it will most likely get the switch advantage. I know that it's not exactly the same, as if the opposing Pokemon is faster then Malaconda and decides to stay in, then the Pokemon you bring in will maybe get a bad matchup where with Baton Pass you can go to the appropriate Pokemon after seeing that the opponent stayed in, but double switching and Baton Passing are not so far away, at least when the Pokemon in question is not afraid at all of Pursuit users.