Many users wish that questions and answers are typeset in LaTeX. There is some hurdle for users that don't use LaTeX very often.
Now I observed my self to use the edit function on my old posts, so as to copy paste some LaTeX to new questions or answers.
Unfortunately I was not able to use the edit function on posts not owned by me. But some source viewing functionality would be very useful, so as to learn LaTeX type setting from others.
The problem is especially annoying when somebody posts a perfect LaTeX answer to the own question, and the source of this answer cannot be viewed.
P.S.: Here is a screenshot: