<b>Interface</b><br>1. Enable view transforming (rotation, zooming and panning) during Object/ObData transforming (moving, rotation or scaling).I think there is no need to comment this. It's just very convinient. And it's possible.<br>
2. Option "Interface highlighting" in User Preferences. When this option is on blender compare two .blend files: current opened file and another one which could be default B.blend file, last saved version of current file or just any file. Then blender highlights in opened file settings (buttons, numeric fields and other) that is different in this files. It will help to learn and make tutorials, to remember what was changed during experiments with blender settings and so on.<br>
<br><b>Particles system</b><br>1. Link emitter's vertices position to particles one (one vertex - one particle). When particles die vertex is erased or stay in one position. It will simplify creating and especially animating specific effects like cigarette smoke or ink dissolving in water or something else like <a href="http://picasaweb.google.ru/karamelin/Blender/photo#5187641518056703858">this</a>.<br>
2. Hair with Halo material renders with noticeable steps (look <a href="http://picasaweb.google.ru/karamelin/Blender/photo#5187641621135918994">here</a>). I didn't find any issue how to correct this. Could it be changed to achieve smooth particles traces?<br>
3. Is it possible to dupliframe objects linked to particles? It's rather question then proposition))<br>
<b><br>Node editor</b><br>What do you think about Layers Node? This node converts frames sequence
into layers with the same odered names. Layers can be processed then with Mix
or Z combine nodes and flattened into one image. This node will allow creating images (or animations) with different phases of objects movement, very long fading traces and so on.<br><br>I hope my bad english did not confuse you.<b><br>
</b>And I'm ready to write detailed description on each proposition.<br>