Add "Auto" as a Font Size Option (and make 'Shrink to fit' better)
I love the Shrink-to-Fit feature in Excel, but it would be nice to be able to select "Auto" as an option in the font size drop-down. Maybe "Auto" would just act like Shrink-to-Fit, but it could be much more.
Working Example: Consider how Adobe Acrobat lets you choose "Auto" as a font size for form fields in editable pdfs. That is essentially the behavior I'm looking for in Excel.
If the Row or Column is set to Auto, then the width/height shouldn't be affected by the cells that are set to Auto size. However, if a cell is set to Auto, then changing the row width or column height should intelligently resize the font within the cell (increasing or decreasing).
Related Example: Notice how images inserted into cells in Google Sheets increase/decrease in size with the cell, even if the cells are merged.
Combine Word Wrap and Shrink to Fit: It really shouldn't be that hard since Word Wrap is already fairly intelligent. However, the line spacing when using Word Wrap could be a LOT better. See the attached screenshot. You only need to shrink the text far enough to make the full text fit within the cell. In the example screenshot, I used a text shape overlay, and the word wrap within the text shape works a lot better (to reduce the line spacing).
Another thing that needs work with Shrink to Fit is to not waste so much white space. Notice in that attached image that there is unnecessary white space after "fit".
Richard Wilkin commented
Combining Word Wrap and Shrink to Fit could mean that if there is a single word, shrink it, but if there are multiple words (that each fit in the width of the column), then wrap it.