I mean 150 speed is good but most scarfers or even choice users( I'll talk about band Staravia later) can one shot easily if you don't run sash
Offense is not the only playstyle. The notion that every team should run offense just to deal with smeargle is absurd really - if something was no problem for stall but could trample over the best of HO teams it would be equally banworthy. Not to mention, things that can outspeed and KO Smeargle are very limited and you underestimate its 110/70/90 bulk. Here's an example of how even some of the tier's most feared Pokemon in the higher speed tiers can't kill it before being spored/voided:
252+ SpA Life Orb Abra Psyshock vs. 252 HP / 4 Def Smeargle: 360-425 (84.9 - 100.2%) -- 6.3% chance to OHKO - [This is
Modest Life Orb!]
252+ SpA Life Orb Gastly Sludge Bomb vs. 252 HP / 0 SpD Smeargle: 320-376 (75.4 - 88.6%) -- guaranteed 2HKO
+2 252+ Atk Arceus Extreme Speed vs. 252 HP / 4 Def Smeargle: 361-426 (85.1 - 100.4%) -- 6.3% chance to OHKO - [Assuming Lum to take the spore, and Smeargle didn't taunt you before you got the SD off]
...I was going to list more stuff, but apart from Staravia none of the rest of the base 151+ speed club is really viable!
Which brings me on to my next point: King's Shield!
It really doesn't have any problems fitting this on over taunt, and it can basically be used to completely deny Staravia and a ton of physical scarfers. As I said, it can run
anything. It also has the benefit of making the matchup against aforementioned E-Killer that much more solid.
-2 252 Atk Choice Band Reckless Staravia Brave Bird vs. 252 HP / 4 Def Smeargle: 261-307 (61.5 - 72.4%) -- guaranteed 2HKO
-2 252 Atk Cranidos Head Smash vs. 252 HP / 4 Def Smeargle: 271-321 (63.9 - 75.7%) -- guaranteed 2HKO
252+ Atk Drilbur Earthquake vs. 252 HP / 4 Def Smeargle: 292-345 (68.8 - 81.3%) -- guaranteed 2HKO - [Not affected by KS but still a physical scarfer so]
I can't think of anything else really.
If your opponent has a grass type Smeargle usability goes down
if you use Dark void you will be able to miss.
Are you really willing to take the risk that your grass type "counter" has an 80% chance of being put to sleep? That's still a very reasonable chance, and even if Smeargle misses the first time it more than likely will have a second shot at it with its usable bulk.
if your opponent has a spinner you need to carry those ghosts and most spinners have Knock off( at least the good ones)
Spinning is far easier said than done without getting your spinner killed in the process. Even if you do predict correctly, your Sandshrew (or whatever spinner you're using) will have at best removed the hazards and died. Smeargle is a HO lead, and the rest of the team will be designed to make spinning/defogging as much of a pain in the ass to you as they can. It's far easier said than done, really.