I’d say the one clear drawback to the all mediums and no QE is the need to inspect more boxes. If you have clearly separated brood boxes and honey supers, checking the brood is easier, as the supers can be pretty much ignored. As I don’t use a QE, I have more uncontrolled volume to inspect.
Now, tbh, if you read Tim Rowe’s book, he doesn’t do frame by frame inspections unless absolutely necessary. He simply recommends looking for signs; BIAS, new eggs, swarm cells by tilting a box and looking at the bottom of all frames, etc., and regular bi-annual treatment.
Running "Foundationless All Mediums with No Queen Excluder". Each box is national spec, but 190mm deep.