Just bought MathStudio express on Android here are a few considerations so far:
1) New feature: Cursor keys for precision movement inside a cell, moving the cursor with the finger is a pain considering how small the font is
2) New feature:Help on each function in the catalog,even a link to the relevant page on the web would be hugely useful and much appreciated
3) New feature:Font size option for the input. A little too small on my Note 5 for my taste,it would be nice if I could choose the font size,if only for the input and the keyboard. It would make a huge difference and It would become usable on a tablet too.
These are the very basic additions I would look for in the future.