What is missing in this discussion of "pretty feet" is in my opinion the differentation between "style" and "function". Style is pretty much a matter of taste, and everybody will have a point in the continuum from parallel close embrace over offset close embrace over v-embrace (half open, half close) to parallel open embrace where they feel at home. Any of these choices will close off some of the potential options of the dance, and open others. The degree of turnout, "tippy-toedness", one or two track walking, and then if leader and follower are on the same track(s) or offset tracks is also mostly a sylistic choice - it will open some options, and close some options, and most dancers will switch between different options - e.g. i have seen the cross system taught as two people walking one-track on two different track, or as two people walking two -track on three tracks, with one track overlapping, and it creates a very different feel, and very different options where to go from there.
What makes a followers footwork beautiful is not really her style, but functionality. each step has to be able to be modified at any time, and the follower has to end up on a stable axis.
We don't collect because it is pretty, but because it makes sure that we are not jumping from a starting point to an (guessed) endpoint, but that we are able to change direction any time during the step without loosing structure. We have turnout because this is how most peoples hip joints work (this is very different from ballet turnout - (which is in my opinion (which might be influenced by the style i tend to enjoy dancing in) not directly applicable in tango - tango legs seem to be conceptually "longer" than ballet legs - ballet appears to value engaging the inner thighs for stability and moving from the hip, while tango engages the pelvic bottom and moves from the spine/below the edge of the ribcage)(and (in my probably mistaken opinion) the parallel stance / pigeon toed stances in martial arts seem to try to talk about enganging the obliques/back to create a unbroken ground path from the foot to the hand (and a turned in front foot keeps the crotch closed - sometimes an important consideration

). We step on the inside edge becasue the way the ankle works means that a foot wont fold over to the outside if we are off, while if we landed on the outside edge we need much more precision and ankle strength to keep the foot from folding over to the inside.
I believe that working on having pretty footwork is at best a detour from working on having functional footwork, and that functional footwork will be pretty automatically.
Gssh