Mmmm, just some ideas ... but no code at all, sorry ;-)

* An arbitrary order FIR filter design opcode from prescribed specs to
implement
linear phase filters in waveguide instruments. tone means a lot of
trouble with phase distortion.
 Implementing any public domain filter design routines would be ok.
* Deinterpolation filters to reinject into the delay/delayw pair at
non-integer positions (like deltapi but writing ... not reading)(thus
avoiding use of multiple waveguides instead of 1 when implementing bores

with tone holes). Docs at
http://www.acoustics.hut.fi/~vpv/publications/vesa_phd.html
By now quantizing time delay to kr integer ratios is quite imprecise
* Ability to import/export graphics to/into analysis files. A really
cool feature this one!
* Standard biquad filters should be implemented, as well as Smith's
reson-z and reson-R resonating filters.
* A conical woodwind ... I´ve never seen one implemented as a PhM
algorithm.
* turnon should be able to be called from inside another instrument,
thus allowing for conditional triggering and some other algorithmic
features...
* 2-D tables or even arrays for Wave Terrain synthesis and automatas...
*Maldonado´s opcodes for cascaded filters to save compilation time
*I saw a nice feedback electric guitar implemented with a modified pluck

alg. at Harmony central, it would be nice to implement it. I have the
source code somewhere...

Maybe I´ll think on more features later on...
Tnx
Josep M Comajuncosas