Well there should be nothing stopping you from writing lengthy, thoughtful posts – there is no 160 character limit, (in fact, there's no limit). There are line

Well there should be nothing stopping you from writing lengthy, thoughtful posts – there is no 160 character limit, (in fact, there's no limit). There are line breaks, paragraph breaks, syntax highlight, black and white (vectorized) unintrusive smileys... And the text box does expand while you type (unlike the one I'm typing into now) and shows you a preview underneath it. Images/video are kind of separate from discussion and tend to draw all attention (you already mentioned signature/etc), but if it's what you need, then this is not the solution for now.