[ken]

Has there ever been a case where a corporation when to a design firm, and the designers came back with "Your branding is already excellent, and we think your best bet is to not touch it"?

(Call it the Miracle on 34th Street response.)

[snowwrestler]

Yes but obviously these do not get written up as case studies by the client or firm.

And you might be surprised by how often the client, rather than being reassured, simply takes it as proof that that design firm is not "with it" since they can't see what is (to the client) obvious deficiencies in the branding.

Generally speaking, brand owners who are happy don't reach out to design firms, and brand owners who are unhappy won't suddenly become happy just because one firm told them the brand is fine.

[blotter_paper]

I personally know somebody who responded to a client in this way, but I don't know of any public documentation of this sort of response happening.