I've been tweaking it here and there and a circle spreading (pushing from inside to outside) will need big changes on the code, so I'll add it to the todo list and push it a bit further back in the roadmap, as I do have a couple of things I want to add first (mainly, layers/emitters).
However, I'll add in the next update a direction slider, that combined with the burst slider will allow to do spiral emission, and I'll also add a min/max direction so it can be randomized.
I don't know what you mean by "turbulence", the results of the simulations should be different everytime you hit simulation or records buttons. If that's not enough, there's a "Morph" button on the 'Properties' tab that will slightly alter the properties.
Looping is a whole other beast, some parameters alter the simulation way too much to allow looping. (Set maccormack weight material to 1 for example, there's no way to loop that) but It's something I want to add in the future by disabling certain features so It's doable. I don't know what you mean with "Duration", maybe that's the 'Burst' slider?