Over on Physics.SE, Emilio Pisanty has pointed out that the proposed new StackExchange editor (currently in alpha testing) would present major difficulties for MathJax-heavy Stacks such as this one. In particular, the design philosophy seems to be leading towards removing the simultaneous preview and towards a more WYSIWYG interface. This makes a lot of sense for posts that are mostly textual; in fact, it would make it easier for newer users who are not familiar with Markdown or who are copy-and-pasting from a rich text format. However, it would also make writing and revising math-heavy posts much, much more cumbersome.
Emilio has written up these concerns as an answer to the announcement of the alpha test. As this change would also affect this site, I would encourage the denizens of Math.SE to take a look at his answer and provide polite and constructive feedback to the dev team via that forum.