As far as I know, abilities CAN'T be broken, only pokemon and pokemon combinations.
Scolipede's support is only broken when an entire BP team receives it. Everyone agrees this pokemon is not broken, so why not ban the combination?
There is a thick line between "how should baton pass teams be nerfed" and "which nerf would the council like the most". Pretty sure this thread's discussion should be based on the former, but so far the best argument towards a scoli ban instead of BP limit of 2~3 seems to be "we ban pokemon, deal with it".
Let's deal with what's broken with as little collateral as realistic, and be done with it.
Who do you want to take the collateral damage : anyone wanting to use the fattest bug or that one player that was playing a full BP team in a non-problematic way?
Even if you think simple bans are worth all the collateral in the world, this will be far from simple to do because Scolipede needs to be defined as the one and only thing that pushes BP over the edge. What if Sylveon, the great Espeon-counter counter could also kill BP teams if removed? What about Smeargle and his sashed Spores? Also Espeon. Sorry.
Yes, I agree with you that an Espeon ban would only increase the ammount of checks against BP, not prevent instawins from team preview, but it helps massively.
No stored power (at least not on top of magic bounce) means they need to buff offenses before one shotting everything, so that alone gives you many more turns.
No magic bounce means hazards such as toxic spikes will start tearing holes or give free turns, plus pokemon with infiltrator statuses, non-haze unaware, encore, non-prankster taunt etc will stop being useless. Roar/whirlwind is also much harder to avoid unless they lead with Smeargle.
No Espeons means A LOT more matches will be skill based instead of over at turn 0, simply because general utility now actually works, so perhaps the point where you are not expected to pack one of the checks for BP might be crossed, therefore Espeon should be suspected too if complex bans are just too damn ugly with clear skies.
Maybe I am just too biased towards being able to use fun pokes instead of ruinning everyone's day for the sake of tradition, dunno.