This is a very old model, and it's as dumb today as it was in the 1990s.

The seniors used to be called "architects," and the "driving projects/design" used to be called RUP.

architect is a higher level, they tell us why our designs are bad

LOL. I feel for you. It's the same way in a lot of places.

Your seniors should definitely be thought leaders, but when they get "too senior" or "too important" to write code, the company is done innovating. That's a major organizational smell.

why is that? isnt the main innovation done in design? anyone can code something up that has been designed for them already

If your design is so detailed that any code monkey can implement it without screwing it up, then you've probably spent more time writing design documents than you would have spent just building it.

And if your code isn't expressive enough that the design can be extracted without major effort, then the two will inevitably diverge at some point. Many bugs will appear.