Yeh, slowbro has always been the premier ph wall, although it's not as good as arcanine against dclaw/return/dedge spam, but unlike any other wall it can start setting up and sweep as soon as toxic users or electric types are gone.
Also noone ranked linoone, so i'll give it a try.
Linoone B+.
Linoone, if used correctly, can often give you easy wins when your opponent has no ghosts.
All you need is to get rid of ghosts, weaken steel types a lil bit and unless your opponent is running hyper offense you will get your chance to setup.
Bulky starmie, fthrower arcanine, slowbro, venusaur, umbreon, ludicolo, vaporeon, cloyster, forretress. weezing without haze, etc. there's just so much it can bdrum on and so little you can do to prevent a sweep when your teambuiling is unfavorable.
However thief isn't enough to 1hko dusclops, arcanine can take an espeed at +5, skarmory and forretress can live flail and aerodactyl can live extremespeed.
As long as any of these things are involved linoone won't be able to sweep and you're almost guaranteed to meet at least one of these.
Totally outclasses any belly drum user, it has the most devastating moveset of any setup sweeper and it is by far the easiest one to correctly setup with.
Risky, possibly useless against some teams, but it will win you some matches just by clicking on bdrum at times.