To answer some of your questions;

1) Is there a way to have each minimized account in the navigation pane indicate for that account whether or not there are any new emails without expanding the account?

A) Try creating a rule that will alert you when an email arrives.

2) Is there a way to have ALL new emails for ALL accounts be indicated in a global inbox?

A) This cannot be done. Microsfot has indented this, since you connecting to multiple accounts each would need its own default folders.

3) What I'd like to see is whether or not there are any new emails by just glancing at the navigation pane.

a) Since no option exists to have the account name display the inbox number, you might want to add each inbox as a favorite. The inboxes will them be located under favorites.

Hope some of this information was found helpful.