You recently added the particle.material to the PARTICLE struct. I know that this material slot is for assigning materials to decals, but I think it could be a good idea to make it also possible to assign materials to normal particles.

Of course it won't make sense to give an effect to a great amount of particles, but it could be a possibility to have a solution for special effects eg. when there are only a few particles that need correct alpha sorting; this should be possible via ffp effects. Such effects could be achieved by using Entities (sprites) as well, but I think it would be faster and more simple to use particles, as one hasn't to care about movement or collision detection when using particles and the particles don't use geometrie which should give an advantage compared with sprites, too.