That all great, and I am a 35 year pro engineer. I agree with the OP. If QSC can put one in the Touchmix, and A&H can put a “D” mixer in the Qu series, there’s no reason a feedback suppressor shouldn’t be in there. It’s great to say, “well, a real engineer with a well-designed system doesn’t need it.” Real world: many of the users of these mixers are musicians and small bands, without well-designed systems, and in rooms that don’t allow proper speaker placement etc. Myself, I can ring out a room with anyone, but when I have a big corporate project with 10 lavs in a far less than perfect environment (and not enough time to set up), my DBX AFS-2 is an invaluable time and aggravation saver.
So I’m 100% with the original poster. Please DO incorporate a feedback suppressor!