I actually meant to delete "ideally, we could set the depth in preferences" and ended up pasting it in again.

The arrow beside Universe could be used to show ungrouped items belonging to the universe; e.g. ground, lights, props, etc.  Basically anything that is a single object with no children.  Because just having "Universe" unexpanded by itself is useless.

So my preference would be when collapsed the Universe would still list all compound objects and figures below it.  Clicking the Universe bar would expand it to show the extra ungrouped items (lights etc.).  Clicking the arrow would expand/close all items.

Goals for improving would be:

1)Trying to keep the arrow behaviour consistent with the visibility toggle.

2)Trying to always show compound itesm such as figures, clothing and compound props.

3)NOT defaulting to showing every single item in the Universe.

And while were at it, I think things like Goal/Center of Mass and IK could use their own check boxes at the top along with deformers, lights and cameras.

It's a matter of making it convenient for more than one style of working.  I don't use the balance tools, so I don't need to see goal/center of mass when my list is expanded.  I rarely change IK settings within a project, so again those expand my list undesirably.  The current behavior seems to be a hold over from when most Poser scenes only consisted of a few figures and props.  The addition of center of mass and IK to the list is only a small amount of clutter, but now many users are navigating scenes with more figures, more lights and many more props.  The hierarchy panel today for many users seems to exist in constant flux between showing too much information and not showing enough.