You act like i didnt read your post and repeat. I did. I don't agree that the result is the same.
There is knowledge in say using AA in place of spread under overheat. You know that it's optimal to use it. You make a decision when you hit AA instead of spread.
If you make them the same button, you are not really reacting to the fact you just overheated, you are just doing the same thing like nothing happened.
As you pointed out, AC has a faster GCD which makes it a bit different.
Now, if we wanted to prune buttons i'd understand, but i don't share the opinion that it is necessary and i do think something is lost by doing it.
The thing is, we can put every rotation in a single button that just changed to the next in the rotation. It is optimal. But, is it fun? The fact that you have to make the right decision on what to push is what makes combat feel good when you perform optimally. Losing that makes combat mindless.