The models and tools levelling out is great for users because the cost of switching is basically nil. I'm reading people ITT saying they signed up for a year - big mistake. A year is a decade right now.
Now with Opus 4.7 of course the “burden” of adjusting reasoning effort has been taken away from you even at the API level.
In my experience people don’t change the thinking level at all.
Codex is abysmal for UI design imo.
But if you go information architecture first and have that codified in some way (espescially if you already have the templates), then you can nudge any agent to go straight into CSS and it will produce something reasonable.