I have not figured this out clearly, but will write down lest I forget. To me it seems that step size choice is also dependent on quality of upper body movement. This is just the feeling after 10 days of experimentation.
What is looking good to me? Staying in balance, staying in control, if losing control, recovering gracefully or in a fun way. If you fail, you accept it and then there is no fail. Then there are interpretations on what you do with control, what do you express, how it works with partner and music, what it evokes in me. Objective part is about balance.
Every body type (height, weight, length of legs) will have different range of steps where they can keep balance and change direction in a controlled manner. Without jerking, falling, slipping, tumbling, pulling or pushing the partner. (I'm not saying these things are wrong, but they're not exactly a signs of great skill.)
In the middle of that range is the comfort zone, and it's not that interesting to look at. At the ends there are very different dynamics. With the small steps you have to direct energy up and down, because there is not much horizontal momentum. So you rise your feet and transfer this movement through all the body; let it reach head and fingertips.
With large steps you will start skidding (depends on floor and footwear), but you can do more, if you use upper body to shift balance in the direction of the step. You're asking, what if one doesn't engage upper body? Then you fall down. Now, this is again dependent on your body type. Heavier person will find it harder to shift and bend quickly. If people lack flexibility, they won't be able to bend joints quickly and in controlled way either. Big steps won't work.
I can't prove this, it's just hypothesis, would be great if we had some qualified person here to set me straight.