you can better say it like this:i think that bans are caused on 3 things.
cause it is clear that your opinion isn't what the majority thinks.the majority already has banned things that don't overcentalize,don't allow easy set ups nor they allow easy stall stups(i don't even understand what you are saying but anyway).whcih are these things?evasion raising items,evasion raising moves and ohko moves!
it's not so much for doing overcentralization, but having the potential to. DT and Mini were banned because if allowed, the metagame would be all about having to build teams around countering DT, and since almost every poke can learn the move, it would just be a DT-happy metafest. stall is also a factor for banning back then- could you imagine how bad Stallrein would be if it had DT as well?- and the 2 highest HP pokes in the game and the first ever Magic Guard Poke had access to the +2 minimize, and all 3 could do a combo of Mini/Sub/ Soft and stall all day. SV and SC do niether of these.
Now the major reason you have for them being uncompetitive is because you can't counter by switching. allow me to present: Speed boost. this ability give a +1 boost in speed every turn, can'tt be countered by switching, AND got a poke banned for it! going by your logic, would this not be suspect for uncompetitiveness? free power boost, can't be countered by switch? one user has access to tail glow which does +3 now, another HJK, another is one of the fastest pokes in the game and can baton pass! and it is possible-Moody got banned for similar reasons. yet, only the USER OF THE ABILITY was banned. see my point?
"don't blame the ability: blame the user." that's why everyone is up in arms and making topics and such, because there are similar things as SV and Sc that are more suspect. there are a ton of pokes who can BP DT. anypoke cn hold the hax items(so i kinda see the banning now, to an extent.) but SV and Sc? stuck to the users.