I hear your point... so in my experience so far whenever I had highly planted tanks - even with low-tech - the plants provided plenty of oxygen and there was no need for extra aeration. I am aware that many of the Discus tanks are planted very minimalistically - there you would certainly need aeration. But in a highly planted nature aquarium (which I intend to build with this set-up) I would imagine plants should be more then enough to keep oxygen high for its inhabitants.
I have been considering maybe adding some airstones to the sump and putting them on a timer - to switch on during the night when everyone is asleep and bedrooms are in the upper floor - so this wouldn't bother anyone. I will need to see how that might disrupt the CO2 though...
And I am thinking of adding a dissolved oxygen probe (in addition to pH probe), so that I will at least give me real data on what O2 levels are in there.