Viewing the potential live output when editing a question or answer.
I have just raised a Q and A but when editing the answer (that involves a picture) there is no "live" version of the potentially finished post and this will prove to be a problem when making a complex answer especially if MathJax/Latex is used. SE.EE does support this feature and I think it's vital.
Also, there is no facility to renumber the bullet points. If you look in my answer, there are two bullet points names "1".
This is what I see when editing an answer: -