I today agree, that devs being part of the creative process and not being drones leads to more happiness and has a lot of upside: they bring new ideas to the table, are more invested in the solution and feel owner ship -> quality of outcome is better.

However, in my experience working on a big product with multiple teams, the main problems with devs getting creative is

(a) the consistency of the user experience suffers badly

(b) the overall architecture erodes as everybody builds particular solutions fitting their specific problem

I am not sure what the best way is to reconcile Dev happiness and (a,b) in this context.