I know it's more development time , but this all helps to create pleasing workflow :)
The thing I find about modular apps is the sameness of the gui's can get a bit tedious to look at.
+ Would be great to have custom colour schemes of the gui
+ Ability to add custom GFX to the modules (think this will make patches and racks more pleasing visually and make the app more appealing to potential purchasers in videos online). Eg adding custom images and rack logos, backgrounds + patterns etc.
+ more knob/slider designs, or ability to custom design the look of them.