The main reasons why I would like to be able to personalize the post editor is because more often than not I do not need to see a preview of the post, it pushes the input section off-center and it wastes space on screen.
I understand there are people who need to make complex posts and therefore have no use for a personalize setting to auto-hide the preview. I feel that having the option to personalize the preview could make Discourse forums more user friendly for people who use the forum like me. I am not suggesting that there is any rush to incorporate this feature, simply that it is worth considering how different people use the forum even if it is not the most popular usage case.
Thank you for replying Jeff. Have a great weekend.