Just curious, is there a reason you have to believe that Super Mario Odyssey will have worse IQ than this?
Right now, pixel counters have it marked as being 720p, but everyone agrees that they're probably going to do an optimization for docked mode with all the time they have between now and its release later this year. Splatoon 2 is also 720p in docked mode presently, though the developers did mention that they're going to be fine-tuning the graphics as the game appears to be more or less content complete at this point.