Disagree. Sure, many people with a negative opinion about Swift haven’t heard more than a few of her tunes. That doesn’t mean she is either deep or a great singer. For discussion of her use of Autotune, check this webpage which isn’t too bad: http://www.savingcountrymusic.com/once-and-for-all-does-taylor-swift-use-auto-tune/

As far as autotune goes, in terms of music, it is a scourge upon the land which allows people with little ability to sing with apparent competence, perhaps never to become good at what they do. The people who do most of this are malleable and cooperative, something which is important to the powerful folks in the music biz. However, as the above link mentions, Swift has sung off tune in concert so often that she probably is not the biggest abuser of autotune.

While I agree with her criticism of i-Tunes and similar streaming services which pay artists almost nothing, I doubt whether that self-serving ethical stance would extend to subjects of great importance which do not affect her.

She is mediocre. That is not changed by the size of her fan base.