When I think of how a lens bokeh 'looks', its not just the "out of focus" area but how the transition from the plane of focus to the far and near areas in the photograph look. The term 'smooth look' has been in general use to describe this.
The other thing I value is a 'creamy' general look without [defined but not] sharp edges or swirling patterns that can be a distraction ( unless the bokeh is your main subject ;-)
The aspherical lens designs seem to have a sharper drop off of out of focus area, not a gradual 'smooth' transition, and maybe their high contrast can even add to this feeling so in general they are not my favorite bokeh lenses.
But older designs because of their inherent design flaws seems to add a signature feel that is valued. Add to this that most of the older designs reach their optimal aperture at a few stops down I see the best bokeh not at wide open but as an example with the 35/2 Summicron in the f4-f5.6 range. Distant of subject adds another element as lenses perform differently being close-mid-far focused.
Complex leaf and foliage may not be the best subject to judge bokeh either. And unless you make a lot of outside in the woods photography (and in daylight stopping down would the norm) its not the usual background/forground. So in general more solid elements are a better judge of bokeh. Subject, aperture, distance, film, lens and personal taste all have a say in 'bokeh'.
Some of my favorite bokeh lenses: 35/2 Summicron 1-4 versions, 35/1.4 Summilux pre-ASPH, 50/1.4 Summilux pre-ASPH, 90/2 Summicron pre-ASPH
