Someone once told me this, regarding my survival:
"Could a team of skilled players, not knowing what awaits them, handle what your map/mod throws at them? If yes - it is a balanced, well made map/mod, if no, then the map/mod needs more work."
I truly believe it's possible to make a challenge without making the player know by heart what awaits him and prepare for that challenge 5 minutes beforehand.
Or at least give some heads-up that OP units are gonna come - by first sending less Op units of that same type as a warning.
You say air can handle a Dream ripper. Ok. Gap of Rohan - you see the Ripper far too late-by the time you spot it it's very near the middle, eaning it will hit the base 20 seconds after that. How do you counter it, other than not having a ton of gunships already prepared? You cannot.
So, the weakness is not really a weakness in small maps, is it?
Why is it a problem to nerf the damage to non-insane levels, and instead boost hp for example?