> the particle sprayer is there so you don't have to make your own...
That's true, but I'm not sure it's worthwhile making the particle spray object increasingly complicated with more and more properties and controls until it can completely match what you can do with Sprites. If you want 100% flexibility, I think the best thing to do is just use Sprites - it'll run just as fast as using the advanced controls on the particles object.
I thought it was a pretty basic feature really... perhaps that it was overlooked when making the particle sprayer in the first place.
I guess I'll have to go write events for gravity and use tint shaders and stuff to custom make what I want :/