In Photoshop, the legacy of the Swatches panel is just color references ("archives").
There is no link between the swatch and the object filled with this reference color cause of the Pixel based original purpose of Photoshop.
But now, that we use Photoshop for graphic design and webdesign, we use a lot Text layer, Shape layer and Layer Styles.
In Illustrator, by default, a basic swatch is also a simple reference/archive, but if you double-click on a swatch color and check Global in the option, the future objects (fill, stroke, pattern...) which will use it, will be linked with this Global swatch.
So that, you could edit the value of the swatch to modify all the applied color at once and sync your modification!
Here a video explaining in details my feature request:
https://vimeo.com/84398366 (PW: request)
What do you think about that idea?