Howdy,
Considering that this rig is work in progress probably, and if the suggestions box is open for submissions, I have a few possible improvements regarding the quadruped auto-rig:

1- I think the spine should be non-stretchy by default - stretchy is very situational;
2- I did not find a way to make the neck non-stretchy; Is there? There really is no need to have a stretchy cervical spine for a realistic animal - one needs to just “model” the skeleton anatomically accurate; idem for the tail;
3- the head could use a pair of ears and a jaw bone/s
4- it seems that there are no phalanges rotate ctrls (hoofed feet)
5- the scapula bones (which are wrongly named “clavicles”) seem to be controllable by a box null with translation; and it disconnects from the humerus; from my experience it would be better to animate these with rotation, but they certainly shouldn't part ways with the rest of the skeletal limb;
6- arm options… clearly should be renamed to something like “Quad front limbs”, added on the Quad Modules panel and also added a hip module where you set a few options for hip (see below) or have these on the spine panel;
7- the pelvis bone doesn't need two mobile bones (currently they're build as the scapula bones with a translate ctrl), they should act only as skin deformers; it doesn't hurt to have them, but there should be probably an option to hide those ctrls at generation time;
8- this could be my fault, but I can't generate adequate paw feet to save my life. Apart from that, I don't see the point of having the option to generate multiple bones for the meta-tarsals, one bone deformer is enough and preferable.
9- the auto-rig creation panel breaks after a few element deletions.

This is it for now. I'm curious what others have to say as I'm sure great ideas and observations will surface from this discussion.

thanks.
I'll keep these notes in mind for future updates.

Sure Michael. Other feedback on this is bound to come in and I reckon we'll have great auto-rigs after a few iterations.