Decoy was only as broken as it was against noobs. The dev team didn’t have that many problems with it. Wraith was a bit strong, but public opinion was the sky is falling.
TRS is smart enough not to release something completely broken which means only some adjustments will ever be needed. It doesn’t matter if something new comes out that needs some adjusting, there’s no harm in it. They release something, they wait a month to see (since people have proven their knee jerk reaction to everything is to cry) how it is, and adjust as needed. What benefit is there of adding a PTR step to that process? There’s nothing gained.