I think the reason for it duplicating the last item in the list is that it makes it easier to deal with point-lists and transforms for instance. With it "remembering" the last instance for the rest you can quickly make a translate array providing only the transforms and adjust rotation and/or scale in one line instead of making separate lists containing the same value. Definable behaviour on the out-port would probably be nice though.
A workaround for the slider range is to publish the port and then right click on it and edit details (also sets default increment size). Also for easier placement, add a layer under the images you want to place and then use that as a guide to place them on the canvas. An additional way to attack it is to snap guides to the center of a selected layer in AI(? I just use Phototshop, but I'd guess you get the same info in AI?) then observe and note down where the center point of the layer is. Then it should just be a matter of typing in the coordinates.
I think this has been discussed before, have no idea where - probably in the km that contains the beginnings of the Vuo 2.0 redesign.
The reason for the colors being what they are is that they are compatible with the Brewer color scheme for color blindness iirc. I think one of the options that came out from the discussion was that there could be a possibility to create your own color scheme and so on - but it might be me misremembering as well. Composition notes will solve a lot of the organising challenges though.