here's an example of particle sprites that rotate toward their trajectory
Thanks, had a look at it.
What he is asking for is tangential allignment of the sprite to the flight path.
Exactly. The image showed just one particle's trajectory for the sake of clarity, but it's about ALL the particles.
Trails would be kind of useful too but are different and would probably be overkill for an emitter.
Yeah, that would be like particles on top of particles (which is available in those pro packages as well, but surely overkill here). Also - trails were pretty easy to implement and seem pretty resource friendly as well:
Just doing some testing and about 4 to 5 objects at any given time are enough to make a serviceable effect (looks better in motion).
Also - those tiny missiles can be used to illustrate the point - if they always faced straight up or rotated randomly it wouldn't look right, same with certain particle effects, hence the wish for this option.