You can preview title by copy-pasting it in the body of the post.
That said, my opinion is that complex formulas should be kept out of question titles, and in general TeX markup in titles should be kept to a minimum. Titles are shown in many places where TeX markup is not rendered: title of the page, filtered questions view (on stackexchange.com), hot question list on other sites. SE app for Android does not render TeX in question titles either. In some places where TeX in title does render, it degrades the layout. On top of all that, markup-heavy titles hinder search algorithms and thus decrease the visibility of question to people outside of SE.
So, I'd rather make it more difficult to use markup in titles, not easier.