Why haven't I seen a champion like this?

I've been looking through the boards every day for the past week or so and I just thought of something that I haven't seen before: What if there was a champion who's CDR didn't reduce their cool-downs but instead factored into their abilities in different ways? Perhaps they have an ability that slows and then stacks the slow as you keep landing it? And then having your CDR factor into the damage? Or how about having an Ult that gets rid of the CD on one of your spells for the duration? These are just a few ideas I wanted to bounce around and see if anyone else could come up with a kit because I'm stumped right now, I'd like to hear what you guys think!