This is the iOS call for TeX support analogous to this request for Android.
That really says it all, but in case you need convincing that many posts on Physics and Math are nearly unreadable without rendering TeX, I present screenshots of the sixth highest voted answer on Physics.
Above is the iOS app, v 0.1.20. Below is the same page on mobile Safari.
Whether it's done through MathJax or some other interpreting, TeX really needs to be incorporated in order for the app to be worth using at all on sites that employ it.