Gimmicks don't do all the work. If that were true you could set an invisible deck on the table and it would cut itself and reveal the card without ever touching the deck.
What you're describing at the end of your post has nothing to do with gimmicks, but with poor showmanship. A pure sleight of hand trick won't be any better than a gimmicked one if you can't perform well.
Contrary to what many people think, gimmicks require a set of skills too use well that is just as comprehensive as pure sleight of hand.
I understand what you're getting at, and perhaps I phrased things a little off. I did however mention that I tend to dislike things like gaffed cards, unless I can develop an appropriate routine to use them in. And the same would apply for a gimmick, but personally the gimmick needs to be simple. Something like invisible deck and hovercard... simple, suspense, showmanship, etc.
I've performed the hovercard trick for an audience of around 60 people and incorporated some science behind things, but started everything out with an ACR before ending with it. It was a truly amazing moment with a great reaction with the audience.