I'm a new user, coming from Illustrator. Unless I've missed something there seem to be some oversights in Designer's colour handling.
1. I can Create Palette From Document to add used colour swatches, but these are always non-Global swatches. Although I can then convert them to Global swatches, the illustration colours aren't linked to these swatches. Illustrator correctly creates Global swatches when the Add Used Colors / Add Selected Colors command is used. In commercial design work it's common to have to edit colours in an existing file, and Add Used Colors is used a lot, for example to remove any 4-colour blacks or find incorrect colour mixes.
2. Likewise Select All Unused is a commonly used command in Illustrator. When preparing files for printing it's useful to be able to see exactly which colours appear in a file and to be able to delete and edit them. Illustrator has a strange way of doing this, where you Merge swatches. Personally I think Indesign handles this better, using a dialogue box.
3. Illustrator's Select Same (Fill, Stroke, Stroke Weight) command is also something that gets a lot of use, for line drawings and diagrams. I've added a comment to a different thread that is a feature request for this.
4. Not as important, but it is useful to be able to see colour splits without editing the colour swatch. Indesign has a Name With Color Value option and shows the CMYK mix when you mouse over the swatch. Illustrator uses the CMYK values as the default name when creating a new Global swatch.