But your comment here is very definitive and is a major problem at how quick we are to defend Valve when we don't actually know.
Of course you won't have modern input controls, since you'll be left to either MKB or XInput which lacks gyro and more.
Can you provide any evidence for this claim?
Like I said, it won't have all the modern features as it will be stuck on a MKB profile or a Xbox gamepad profile (or whatever you configure). But it will work