the problem with air units

They say Banshees are broken. I don’t think so. But I think there is a problem with the damage dealt to buildings.
Basically, right now T2 air is a lot more cost effective for taking out bases compared to T3 ground and air. T3 units already being a lot easier to counter.

Either T2 air building damage is too high, or T3 (ground and air) is too weak.