Sadly quickbans like that tend to be a necessity early on so we can have some idea of what the meta even looks likeNot a huge fan of liberal early quickbans UNLESS the plan is to retest them later as the meta settles. I also highly encourage at least waiting until stuff like revival blessings works properly (who knows what else isn’t working properly).
Despite that, I wouldn’t complain about a flutter mane quickban that is never retested at the very least lol.
On my experience chien Pao is an absolute menace, the amount of times I played badly but managed to get a swords dance with it due to shed tail support and turn everything around is insane lol. Also helpful that it speed ties flutter mane and it can get sucker punch, which absolutely trounces it.So besides Fluttermane, who I imagine is gonna get jettisoned...
Early gen has not been that bad for stall all things considering. Unlike Dynamax and a bit unlike Z Moves, there does seem to be the real ability for stall to utilize Terrastialize at least somewhat effectively. The one given to me was a Terrestialize Avalugg to fighting type, which does turn an otherwise garbage mon into a pretty good physical wall. It's actually really cool when you get to do something like this. I do think Terrestialize is probably broken, but only because we don't know the full extent of how to utilize it yet. IMO the current mons that are broken terrestializing are just broken mons. The adaptability part seems like it should be an issue but I can't say with confidence its not just incredibly busted mons making use of Adaptability right now.
The Pseudo legendary dark attackers Chien-Pao and Chi-Yu are... very very strong. Stall has an adequate wall in Blissey for Chi-Yu but the cut to your defensive stats + a potential spec/band pairing and then terrestializing on that is ridiculous. Even without Terrestializing, its very strong (overheat specs Chi-Yu can chunk a physical defense azumarill for 60-70%?). I've not seen enough of Chien Pao to know if this is another problem specific to less bulky teams or if it can do in a defensive team too, but so long as Avalugg is able to go Fighting type, I don't think its gonna be a stall issue.
Lastly... There's a real weird lack of good defensive grass types this gen. Amoongus is here but being ground neutral with the kind of teams Stall wants to run is a bit of a bother (Clod+your ghost type probably being ground weak). Hisui-Decidueye will probably be a welcome defensive addition as a fight/grass but as of right now, if you can't run Amoongus, you probably have no grass option at all other than Terrestializing something.
The one stall team I ran into with it, it put in quite a bit of luck because they ran clodsire+ corv + skeledirge, but tera avalugg actually looks like a good wall for it