They were cool...in 1890. Why go with a revolver when there are so many better choices. If you shoot a revolver better...more power to you. But if you need that reload and you're not Jerry Mickulek ...you are in trouble.
I will maintain that if you have to reload as an individual in a gun fight, you're already in serious trouble. I carry autos, but for those that shoot a revolver well, I don't see why they wouldn't be relevant. Get rounds on target, take cover (or at least move!), reload if necessary.