As someone closer to average rank, do I think T3 air is OP? Not really (if anything, it's weak vs T3 AA and MAA). Strat rush can be devastating but usually only when there is a power crush or huge imbalance in air, which generally means one team is already way behind.
One thing mid-level players often do is too much "optimised" eco. Turning this style of build into a strat rush isn't hard. The problem is largely team mates expecting not to need any inties or AA and not doing enough aggression.
There is a very big gap between inties and ASF, which doesn't make things easier (excepting Aeon).
... perhaps one of the biggest issues in FAF is that among mid-level players, eco-heavy defensive builds work just often enough that many players choose this approach too often. Then, when put on a mixed team, the lack of coordination causes the whole team to do poorly vs a coordinated but mediocre team. I'm not sure how to fix this. (Dedicated team captains? Forced voice chat?? Give up.)