In addition to a Shetland pony, I would love have an information readout attached to the text box in Publisher that would show me the paragraph measure (number of words per line) of that text box.
Spitballing here but something that would:
For lines that have words in them
1. Count the number of words.
2. Average the number of words vs the lines that have words in them.
3. Display that number somewhere I can see it while I jiggle the handle, like the toolbar thingie.
In a fairly lengthy meeting, you could have a heated discussion about whether the calculation should be performed before the auto-linebreaks and assign some sort of decimal weighting based on the overhang of the words that break the line or whether the calculation should be performed after the auto-linebreaks because that's what users see anyway. Either of these options would be fine with me, I would happily get the coffee and pastries from the kitchen to make sure no one dies of malnourishment during the meeting.
This feature would help me make nice readable blocks of text. Or dense impenetrable text when I'm feeling mean.