I would generally agree, especially since OU is all inclusive anyway. I guess i would get a different response from the UU forum, which would be more interesting. But I want to stray away from Mamoswine and focus more on how people feel about this kind of influence from one person. For example, would OU players really care if something like Kommo-o was brought into OU because one person was able to influence others to use it repeatedly? Just food for thought.Mamoswine was OU last gen and still has plenty of viability in this gen. 130 Attack powering probably the best STAB combo in the tier (the only relevant resists being Rotom-W and Araquanid), plus some set flexibility. Mamo could conceivably stick around.
If there's any anger at Pokeaim's tier manipulation, it would be over Ambipom, a mon that was notorious for being tiered too high last gen and even after gaining Tail Slap this gen is mediocre at best.