Ok that was easy!
Yes, it is very useful to use spark as a controler for other drum vst. (I am glad that at least this works!!!)
I am not a professional but my proposal for the team is to integrate a midi live recorder/sequencer which is unlimited in time in the spark. From the sequencer, which could be a very simple structured one where only the necessary features are offered, it should be still possible to drag and drop the midi files to e.g. cubase.
That would make the spark way more useful.