Particle deformers:
- Non-linear: bend, taper/flare, sine, squash, twist, wave
- free-form cage deformer (customizable matrix)
- sticky particles (with 'sticky-ness' customizer, gravity editor, and ability to splat/radiate from contact point---hello gib-tastic particles!)
*edit* forgot to add, trail particles that could potentially be based off of a spline tool similar to road tool
(not just 'trailing' off of a geometry's animated motion)