My ideas are more workflow based, though I welcome more TAE, PM sounds and samples to Spark.
When I'm in the Library dragging and dropping drums from the 'Library Instruments' to the 'Loaded Instruments' and I'm constructing my own custom kit, I find it hindering that you can't hear the drum sound you are loading. It would be so much better for constructing kits if you could hear the drums you are putting together to construct custom kits. I would think when you click on them in the Library you should be able to hear them.
On the hardware controller for Spark LE, I would like an alternative way to press 'Enter' instead of clicking the big knob. It's a neat idea to be able to use knobs as buttons, but I prefer the buttons on the Spark LE much more. I would like an alternative 'Enter' button, in other words, be able to use a single button or a combo of buttons ( like the Loop 'On' and Inst. buttons together) to be used as an 'Enter' button. And also, I think having the Tempo knob double as 'Shuffle' (maybe by using the select button, would be nice. I heard a way to select an 'Accent' button is in the works, so looking forward to that.