First of all I hope our current language already protects us from geared turbofans or any anything else by default. We can't write in every type of conceivable propulsion system and hope we don't miss one.

But in any case, if we don't start lowering the total seat count we allow to be outsourced regardless of how its powered or how much it weighs, don't be suprised when we order 255 (or more?) 70-76 seaters, or 500+ 50 seaters with high bypass turbofan jets made of ultra light composites or even this:
Scientists Develop World's Lightest Metal, 100x Lighter than Styrofoam | Inhabitat - Green Design Will Save the World

Sure the 50 seaters are a dying breed now, but when technology catches up and a new one is made that offers a lower per passenger fuel burn than a 320 NEO or a 737MAX, they'll dust off Fred Reid in 2 seconds and he'll order a thousand of them. Don't think it can't happen (again).

That being in our opener shows we are thinking two moves ahead. Great. But the corporate mercenaries are thinking 8 or 9 moves ahead. We need very broad language with no room for "interpretation" on our scope. Black and white. We own it, not any other group. Period. I don't want to have to worry about some arbitrator's opinion 10 years from now regarding cut throat DCI carrier #12 and their 300 firm orders for 76 seaters or even 130 seaters powered by some new extreme bypass gear reduction frictionless bearing semi-fowler ducted internal double reverse annular flow fanjetprop.

C2012K needs to at least lay the groundwork for, in the near and medium term, to sharply reduce DCI no matter what powers the planes or how much they weigh or how much hub to hub they do or what snacks they serve on Tuesday. Period.