As Ion stated in the interview, it's a huge inconvenience to be expected to swap for literally everything you fight. Even with being able to swap then and there, you'd still be wasting time doing it constantly until an addon is swapping for you - and at that point, what's the point of talents if not the choice in having builds where you differ play from others of your spec? If we get rid of what is meaningful of talents, then you effectively may as well not have them at all. This would result in so much homogenization people would complain that everyone plays their spec absolutely the same, because of course they would there wouldn't be any talents effectively at that point.
If you decry for the elimination of convenience for this kind of swapping you're either inadvertently asking for homogenization or a destruction of the entire system. It's fine if you think it'd be a better personal experience, but there is another section of the community who understandably sees things completely the other way and would if anything want more variety and options to customize their play than not having any options at all. On bleeding edge customization seems like a fever dream, and hell even casuals nowadays feel pressured to optimize things like Covenants, but I'd argue people would just complain about lack of gameplay variety if they all played the same. The illusion of choice still has to be there to satisfy the user even if the choice is being made with numbers for them.