There are other pokemon that can KO Unown Q first turn, but they aren't actually ran in currently competitive decks. I didn't see any Farfetch'd at Nats.
The only real (meaning people actually run the card) risk for T1 KO of an Unown Q is Unown Q itself....
Thus you can't actually T1 someone's Unown Q, unless you actually run Unown Q.
Thus if you think it is crazy to risk running Unown Q, the only way you can lose is if your opponent is crazy enough to run Unown Q.
I am wondering if I have Unown Q with 30HP and Unown U (LA) on the bench, that would probably counter the Gardevoir X "bring down" attack. Would this be an useless idea or would it work? If it works, that would be another use of the Unown Q.