Loving Cubasis, specially now with the Iconica Sketch and tempo tracks! Very useful!
Some ideas for a feature request:
Video player support (MP4 at least),
(Please make sure to have a button to be able to move the transport frame by frame, forward and backward). Please make the video window movable and resizable, even tiny to full screen if possible.
Markers Track
Render in Place
A Deesser plugin
Magneto 2 (why not?) 
Video Render Export with the music done, (or a Replace audio in video file)
Kontakt Vst support and its samples
VST support from PC plugins (on android).
Score Editor for the Midi tracks, with pen support
Maybe Cloud folder sync for projects in GDrive or Dropbox.
Soundly integration for SFX editing.
Model-E (from VST Classics).
- Minisampler overhaul with better/more functions!!
Performance Mode, or even just a skin, really, that makes the Play button bigger, removes the Record button, and lets you queue your next song. Using Cubasis on stage for live performance can get dicey with all those features/options getting in the way and crowding the screen.
Either that, or they should just come out with a slimmed-down performance app that plays Cubasis Projects.
Call it the Cubasis Player 
From my view no other improvement would be as important as introducing the Cubase Drum Track/Drum Machine into Cubasis - if possible with full Cubase functionality.
iOs Hardware has improved more than enough to make that possible, and mobile beatmaking is probably one of the most wanted features out there.
already a thread for this ; I’ll bump it for you