A couple of wish list item that I would love is to do with marionette I will break down into 3 parts as follows but all 3 are connected into choosing, moving and stretching an item easier:
a new connection marionette that links this new node up to an item/object (Polygon, Group, Symbol etc)
Rather than having to name the item and place a name marionette to save time you should be able to connect the marionette node directly to the polygon so you could have it so you can just drag a special node handle over an item it highlights the item and whatever it is then is connected to the node and have the node name the item automatically or have a manual type in box to override the auto name to simplify users connecting Geometry of any kind to Marionette so you can visually see what you are connecting.
a marionette that will allow you to stretch the named item (from part 1) using bounding boxes have this new node so that when you feed an object connection in it detects the item and then using a bounding box approach like@DomCapproach to stretching an item or something similar to that, where you specify two or more boxes whether they be 2D or 3D and a dimension input on the dialogue with a direction input to choose which orientation to stretch in either or all (X, Y or Z) so you can stretch the item easily in all or just 2 directions (example: you could use this to stretch say the ends of a desk with legs say in X: 200mm increments and at the same time stretch the depth of the desk between 600mm and 800mm depths without having tons of nodes to do this)
a marionette object that will allow you to lock / move instead of stretching the item (from part 2)
On the back of the above have a third marionette that has an input object and a stretch input object and you can pick either X, Y or Z like above but when the above marionette stretches the item this locks the dimensions of the input object so it cannot change dimensions have either a bound box again or named input.
I think the above would speed using marionette massively so you can reduce a massive structure of marionettes down to 3 marionette items/nodes.
I might be wrong but this is just an idea for speeding up workflow in marionette.