Hi Olaf,
There is no straight way to animate parameters, which is just question of time, already want to make it better. There is indirect way - see the green button on right of slider? Channels I mean

. This is a workaround, which may work on simple cases. There is Channel Effect, it can be in same effect list. Basically, Channel Effect move the channel value, and slider linked to channel. Sort of proxy. Of course, channels made for other purpose, and I do not want to say this is comfortable solution. "Green button" made for various real time control from external sources. Animation by time is alike, but still different thing. Anyway, I will make it as better as soon as possible. Still think about UI for this construction.
There is one more workaround, also a bit heavy, based Object Animator and Shape with identifier. Basically, object animator can modify various parameters in real time. But this is too heavy direction.
BTW, Parametric Image is much faster than Shape. If you need simple shapes, Parametric is better.
Best Regards,
Alexey.