I take your comment as true, but that would make the design error even worse. Even in moderately cold temps (single digits/teens) our truck will not clear the windshield on start up/ running without full defrost being utilized every few minutes. Auto doesn't cut it at all. In cold temps (0 to many below), the defrost has to be used even more, negating heat to the floor.My 2019 Ridgeline ALWAYS has 50% airflow out the windshield vents when set to FloorOnly. ALWAYS. No matter the outdoor temperature . I think that this is the root of most everyone's issue with poor heat to the floor.
Next step is to devise a method for removable blockage for the windshield vents.
Without a doubt, the G2 truck is the poorest performing heating system I've had in a vehicle for over 30 years. Maybe more. On the flip side our G1 truck heater was more than adequate. MUCH faster warm up and distribution of air. The AC in the new truck works well.
There is no excuse for this today in any vehicle. As you suggest, I'm sure there must be a way to block the windshield vents, but the whole idea of having to modify a modern vehicle's heating system to just make it adequate is mind boggling to me and disappointing that Honda put this system on the street with so little testing