Compass rose designs
Compass roses are an ideal map object to embellish for a unique map. They have a clear function and simple design that asks to be made more.
The only necessary function of a compass rose is to indicate the direction of north... whether an arrow or a line with an "N".
Antique maps
Antique maps decorated compass roses depending on the tastes of the times.
An important part of antique compass roses was the inclusion of the 16 cardinal and intercardinal directions. This was due to the tradition of maps as sea charts to find the way. Accuracy of direction was important to early navigators.
Many maps went even further to include rhumb lines making bearings easy to figure out.
Modern maps
Modern maps have worked to simplify the extravagance of previous maps. Minimal design of simply the needed north arrow have become common.
Modern cartographers have increased the frequency of leaving off north arrows for maps oriented north.
But while cartographers seem to have the tendency to see compass roses as clutter, map artists seem to see the compass rose as another means for expression.
For example, Mike Reagan often embellishes compass roses to reflect the map subject. You can see an example on his Map of Carravagio's Italy shown on this page (scroll down).
Another unique example in a different direction is Richard Eades Harrison's inclusion of a location map in the form of a globe in the compass rose. Notice that north is not up! He has oriented the compass rose to the same direction as the map. Not unique... but what is unique is that the world location map is therefore not up. This is unique. Most location maps use the north-up convention.