Well I have ... I saw that in the 1975 docu ... still it was decided to stick to only-rectangular symbols when overworking device.lib. I used this doc (more recent!) as source: http://pcad-libs.embedders.org/rules/ref_617.pdf (from Alstom, based on IEC 60617-2/-11:1996). If you look at p. 72 ... no wiggly (unless I overlooked them).
To prevent people from putting in the work which may be rejected in the lib (see it merely as a warning!).
Then you're using an old lib version. In current lib-versions they look like this:
The transistors are old symbols and should (!!!) be overworked, but so far no one volunteered
which false assumptions? If you name them, we can discuss them!
PS: Bottom line is this: During the last year, a large effort has been made to make the lib look more uniform and sleek (and it's still going on, I'm currently e.g. overhauling regul.lib and ther is a PR for linear.lib ...). Based on that and on what we do on a day-to-day basis in review, I strongly suspect, that the wiggly resistors would not be accepted into the lib (and if it's just to keep the lib managable by preventing doubled and tripled symbols that all are the same, just with a different look!). What I would find nice would be support from KiCAD for different styles, as it is implemented for standard logic and deMorgan-form. This way one would have ONE component, just with two user-selectable appearances (I would vote to accept such symbols, if the feature exsted in KiCAD) ...