If an ad campaign is built around a weak idea - or as is so often the case, no idea at all - I don't give a damn how good the execution is, it's going to fail.
It is not the purpose of the ad or commercial to make the reader or listener say, 'My what a clever ad.' It is the purpose of advertising to make the reader say, 'I believe I'll buy one when I'm shopping tomorrow'.
If you have a good selling idea, your secretary can write your ad for you.