Here are some suggestions I think would help improve the app.
Blank template - to avoid having to always change out your drums when creating a brand new project.
Chop to pads option - when working with a sample, adding markers to chop the sample in to several parts and assigning them to separate pads. This would be great for manipulating drum loops as well as samples. Making it much more than a drum programming app.
Shortcut fix for pages (Spark LE) - when selecting the pages (main, mixer, studio, etc.) the sequence is out of order on the hardware. Also, there is no option to go back to "pads".
Sample names - the app does not use the name of the custom sample. Has to be named twice.
Tune - when selecting "Tune", Spark LE pads do not allow you to play the notes of selected instrument. Behavior of pads should change to mimic app.
Update iSpark Manual - please include a section to showcase capabiliand shortcuts using the Spark Le. I've seen a number of shortcuts on YouTube vids but I'm certain there are more not shown that are available.
That's it for now. Great app but could use a few more touches to allow it to be complete production center.