I would love to see an algorithm based around physical-modelled body resonance, something in the territory of Ableton Corpus.

The H90 Resonator is extremely musical, and I use it regularly. This type of effect involve modelled resonant object that incoming audio can excite: string, plate, membrane, pipe, tube, wooden body, metallic body and similar resonant forms.

This would let the H90 add acoustic-body qualities to any source: plucked string colours, plectrum-like attacks, struck wood, metallic resonances, membrane-like drum-head behaviour and tuned object resonance. It could be subtle body enhancement or a more radical transformation of synths, guitars, drum machines, samplers and field recordings.

The value would be that this adds a new family of sound design: physical acoustic transformation. It would sit beautifully between pitch, reverb, resonator and synth territory without simply duplicating existing algorithms.