Srn9130 You are certainly correct that many mons can setup along side you, however, since scolipede usually is faster,
he will almost always get his boosts first. Furthermore, relatively few physical mons can ohko given equal boosts. Lastly, scolipede can pass to whoever he feels like, so if the enemy decides to get into a setup race with scoli, scoli will always at least get a pass off, leaving it to the recipient to counter the opposing setuper. Let us use your megamaw example...
252+ Atk Huge Power Mega Mawile Iron Head vs. +2 252 HP / 252 Def Scolipede: 106-126 (32.7 - 38.8%) -- 99.3% chance to 3HKO
Since scoli outspeeds even without speed invest or speed boosts, no prediction is required here. This means that megamaw's only option is to boost along side scoli. Since scoli is unlikely to stay out once he hits +6, the next calc is kinda irrelevent, but since it is generally agreed that his phys bulk is mediocre, it's a helpful base case.
+6 252+ Atk Huge Power Mega Mawile Iron Head vs. +6 252 HP / 252 Def Scolipede: 211-249 (65.1 - 76.8%) -- guaranteed 2HKO
Now think of all the mons that actually have
good phys bulk, such as dnite, gyrados, charizard, entei, and a slew of other good mons that can come in on what is essentially a +0 megamaw incapable of setting up. They now have essentially a free swap in. However, unlike most times when you swap in a counter, this time the opponent is screwed because he is now facing a powerful offensive threat that is essentially
invincible on the physical side as well as having near infinite speed. Do you know how many threats would kill to have that? Think of all the dragons that hate ice shard, think of all the mons that can be revenged by CB tflame, think of all the teams that rely on priority or scarfers to take out boosted threats that outspeed and kill their team, those options are now GONE. Literally your only hope is that the mon that swapped into mega-maw either does not boost and you have a mon that can phase it, OR that the mon that swapped into mega maw gets cocky, tries to boost, and gets 2hko'd by megamaw. That's way too good of a win condition for the reliability in which scolipede gets his boosts.
You said it yourself! Banning iron defense scolipede balances BP versus offensive, but not defensive! So thanks to your ineffective ban, the entire meta must run offensive teams in order to not be run over by baton pass. Is this what we want to do? The purpose of what we're trying to do here is to make baton pass possible to handle by any team archetype! This includes STALL!!!!
Just banning scolipede doesn't do this, which is why we shouldn't do it.
The reality of the situation is that it will likely take more then a single ban to balance BP. I have been focusing on iron-defense scolipede because 1. I feel he's more broken then anyone else on BP and 2. Because trying to advocate 2 bans at the same time would confuse others, points would've likely gotten mixed up, and I feel that it would've been more effective to argue for one ban at a time. As you have stated, banning iron defense scoli balances BP verses offense, which is one of our goals. The other goal is to balance it versus defense. Offense and defense are two very different things, and it would be folly to assume that one thing breaks an archetype against both of them.
That's not really true....
You can just phaze or just throw around powerful special attacks if iron defense scolipede is on a team without espeon or a special wall.
Now, judging by how you phrased your sentence right there, you're suggesting that ingrain smeargle is why stall can't break through Baton Pass, as iron defense scolipede is what some offensive teams aren't breaking through.
Ingrain smeargle really really REALLY isn't the main problem here! How do you guys start pointing out members of baton pass OTHER than the MOST OBVIOUSLY BROKEN ONE ON THERE!!?!?!!? If you really want to get rid of a pokemon, it's friggin ESPEON holding that goddam team together! If you want to nerf baton pass against stall, it's ESPEON that you need to get rid of! Perhaps that isn't the case for offensive teams, but there's no one pokemon to get rid of that's taking on entire offensive teams regardless, even after a few boosts. Scolipede comes close, but like you said, there are several ways to get around it.
First off, scolipede is not broken because there exists mons that he cannot setup on. Every mon has opponents that he cannot setup on, even e-killer arceus. What makes scolipede broken is the ridiculous number of mons he CAN setup on. I love how you are assuming that scoli can only be led and cannot come in after a mon is killed.
Scolipede works as a lead simply because he is able to setup in front of the vast majority of the OU tier, which makes him broken. If it were any other pokemon, you would be laughed at for trying to lead with your setup sweeper, but scolipede manages to work because in the vast majority of it's matchups, it can pass its +2 defense and speed and still have enough HP to
do so a second time. The fact that he cannot setup in front of tflame is irrelevant, one of the calcs I showed tflame being unable to
counter scolipede because if it swaps in on an iron defense, it fails to come close to ohkoing, even with SR up. It isn't just some offensive teams that have difficulty breaking through scolipede, ALL OF THEM DO, because the vast majority of things that can kill speed boosted threats are
physically based.
You have also suggested that espeon is a bigger problem for stall then ingrain smeargle (it sure as heck ain't more broken then scolipede for anything but stall, there is no long list of uber mons that espeon can successfully setup calm mind in front of and live to tell the tale). I personally disagree. I believe ingrain smeargle is broken versus stall because it requires only one free turn to make the entire team immune to phasing, forever. Ingrain also makes it much harder to wear down espeon through scald burns, weak phys attacks and s-toss, due to essentially doubling lefties healing. Espeon is powerful, but the reason it is balanced is that it needs to be out in order to block most of stall's weapons. Ingrain smeargle only needs one free swap in in order to permanently remove one of stalls greatest weapons and greatly hinder the other. Wearing down espeon is stall's win-con vs BP, once espeon is gone, stall basically auto-wins. Ingrain makes it too difficult to wear down espeon, breaking the matchup.
To further support my point, here's a replay where a stall player would have won had it not been for ingrain.
http://replay.pokemonshowdown.com/ou-110739069
Quoting my own analysis for convenience.
During this replay, denis gets ingrain off early, which allowed his espeon to have roughly twice as many substitutes up while at the same time allowing both espeon and vaporeon to shrug off burn damage. Ingrain healing also made it nearly impossible for s-toss chansey to stop the boosting, as it was turning 4hkos into 5 or 6 hkos, which turned out to be super relevent in the endgame as it allowed sylv to get one more boost off and allowed espeon to live just long enough to take out chansey. Lastly, the early ingrain basically meant that denis feared NOTHING from sandstorm's skarm, who could've turned around the fight by threatening with whirlwind and using BB instead. This threat was not possible, however, due to ingrain smeargle.
TL;DR ingrain smeargle was the reason sandstorm lost this match, and that gives me reason to believe that banning ingrain smeargle will help stall fight BP more effectively with scald burns, s-toss, subs actually costing hp, and being able to threaten non-espeon opponents with whirlwind, giving stall more counterplay options.