Z3TA+ iOS has set a new standard for synthesis capability and flexibility on the iPad, so thank you so much for developing this great product! However, where Z3TA+ iOS excels in synthesis, it fails miserably in user-friendliness. So here are some concrete suggestions I think everyone would appreciate being implemented:

 
1) The interface is CRAMPED! Try spreading the functions over more global tabs to give functions (and fingers) more room. Personally, I'd recommend an OSC/FILT tab, an ENV/LFO tab, a MOD tab, an FX tab, and an ARP tab (this could allow the arp function room to grow in future updates, as currently the arp's in-app midi editing functionality feels a bit restricted IMO). At present, everything is stuffed into just three tabs, unnecessarily cramping the workflow and making accurate tapping a chore. You've done a great job recreating the Z3TA+2 feel and layout in the iOS version, but sacrificing ease-of-use to do so seems like a poor tradeoff.
 
2) Use more pop-up dropdown menus (as in the WAVE tab) or scroll wheel menus (as in the SCALE tab) instead of the endless tapping required for some parameters. For example, transposing an oscillator to -1 currently requires literally 24 (cramped!) taps...that's ridiculous. With a scroll wheel, it could be reduced to just 2.

3) Allow Z3TA+ for iOS to retain previous states in memory instead of resetting each time the app is opened or idle for a while. When editing patches, if I leave the app alone for a while without saving a patch, next time I touch or open the app it resets everything to the init or default patch, thereby erasing all unsaved work. In my case anyway, this happens after simple idleness, even if the app was never closed. Pretty dumb if you ask me.

4) Double-tap a parameter to automatically return it to its default value. This is a quick fix that would speed up the editing process.
 
5) Allow for easy soloing of individual oscillators. Currently we can mute individual oscillators, but to hear just one, we have to mute all the rest individually. With the current cramped interface (see #1), this means soloing requires numerous labored taps. One solution without additional buttons would be to double-tap an oscillator's On/Off button, or to tap-and-hold it to solo.
 
6) Add "Overwrite" and "Save as" to the PGM menu. Z3TA+ iOS crashes sometimes, so to avoid losing work, I save patches regularly; but with the current "Save" button (which effectively works like a "Save as"), I have to retype the patch's name every time I save. Not a big deal, but pretty annoying and presumably a quick fix by just adding an "Overwrite" function.
 
7) Show small previews/pictures of the oscillator waveforms in the dropdown waveshape menu in the oscillators section. The desktop version has such previews, and it's helpful. With no pictures, the waveforms' names can be pretty opaque. Especially if the functions are spread out (see #1), I bet the extra room would make implementing these waveform previews even easier.
 
8) Create an "Undo" function to undo the last step in editing.
 
9) Provide a way to copy-and-paste states between modules. This would allow users to quickly duplicate all of an oscillator's specific parameters quickly, or a filter's, or an envelope's, and so on. Just to speed up the editing process.
 
Suggestions 3-9 would be awesome, but aren't strictly necessary as there are currently workarounds, however irritating and crude. But Suggestions 1 and 2 are ESSENTIAL, as there's no way to avoid those totally dumb problems. So I would prioritize these above the rest.
 
Thanks for reading. I hope you'll take Z3TA+ iOS to the next level by incorporating these changes into the next update. I would certainly enjoy using the app a whole lot more, as will everyone else I'm sure.