There is no autotune for acting..and you can't wear sleezy clothes to make up for lack of voice/talent. I think she has great writers and can let it all hang out with the best of them. But, I heard a version of her live which was quickly pulled off the air. She sounded horrible. Yes, big boobs, provocative outfits, but she doesn't write her music/play instruments etc. Without the flashy outfits and autotune...she would be a dud. Lets hear Katy unplugged...cats even run for cover. As for acting...you are already doing that. Not very well.
Doing a concert movie doesn't make you a "movie star" in the way that most people identify the word.