Firstly, let me congratulate you on having developed the best audio multitrack software in the app store …I've tried a few! So, thank you very much.

The ability to expand to 24 tracks (which I have) is a real USP for your product. On top of that, your app is by far the most stable and I can see from your contribution to the forums that you're all about stability and simplicity rather than lots of over complicated fancy features that don't really work that well …and crash the software anyway! …Massive respect for the way you're going about developing this thing.
Although I have a studio setup where I work with Logic on a Mac, I'm also mobile a LOT of the time and am currently aiming at having the ability to create a track from start to finish entirely on the iPad. I'm using your app in conjunction with nanostudio and it's working really well so far.
I totally appreciate the work that goes into developing an app as good as this, so please don't think me too cheeky by coming up with a list of potential improvements …compiled over the last month's intensive use of Multitrack DAW. It's a fairly large list, but I've not included anything that I wouldn't use in every single song. Also, please forgive me if people have already mentioned any of these things a million times already!
1. Dedicated mixer screen: This could be accessed via a button in the transport bar at the bottom. You could do away with the output VU (if needs be) as it'd be shown in full on the mixer screen instead? Maybe you could even do away with the input VU too if the incoming signal could hijack the relevant track's VU meter when recording is armed?? Don't get me wrong, the method you have of enlarging the mixer controls, mute and solo buttons etc is genius, but can make for hard work when mixing down. Also, it's great to be able to play with the mute\solo buttons whilst looping to get ideas for the song arrangement.
2. Audio edit screen: A dedicated full screen view of a region's waveform with zoom capability to make precise edits. This would be a far better way to edit regions and would ideally include functions such as Normalise, Reverse and the usual DSP options. This also has the knock on requirement of an option to create a new audio file in the bins as a result, or apply the edits to the existing part.
3. Volume / pan automation: This would have to take place in the main arrangement screen so you can see what you're doing in relation to the track's waveform. Maybe each track could have a drop down section accessed by a button or hotbox option? It'd be necessary to be able to draw in the automation both by freehand and some kind of ruler tool for precise point to point fades etc. All of what I've described is implemented fairly well in another app (Meteor by 4pockets). This is the one and only area where I'd have the cheek to point you towards another app as an example. You may even have a better idea of how to implement it in Multitrack yourself?
4. Region repeat / mute: The ability to repeat a region several times over in one operation without having to do lots of copy / pasting …and then moving into place etc. Maybe another button in the transport bar or a hotbox option? You would obviously need to be able to specify the number of repeats. It would also be very useful for arranging a song to be able to mute any selected regions without having to delete them or mute the entire track.
5. Track colouring: The ability to individually colour regions or tracks. Even if there was just a pallette of 24 different preset colours?
6. Region copy: Currently, when a region is given a custom name and then copy / pasted, it doesn't carry over the custom name to the resulting copies. It just becomes another generic name such as "Region 24" etc. I'm getting by with just naming the tracks instead which is fine, but it would be better if the regions' custom attributes such as name and colour were copied with the paste function.
7. Slicing and joining: Slicing audio parts is sometimes a little haphazard. I really like the option you've included to turn snap on and off and this is often enough to slice at exactly the right point. However, if it's necessary to slice a region precisely, but not on a snap point, then another method of slicing is needed. The method you have of moving the song crosshair playhead is brilliant …it works really well, so maybe you could introduce an option that slices the selected parts at the crosshair? Also, it'd be really useful to be able to join regions together, which subsequently may mean creating a new audio file in the bin?
8. Song Overview: Another button or menu option somewhere to turn on a song overview strip at the top of the screen. This would always show a miniature overview of the entire song and let you jump to any point within it. A sort of song navigation device. This becomes even more useful when there's track colouring in place, as you can see at a glance that pad sound in the second chorus that you want to jump to and fade out.
9. Effects: Now, I totally appreciate this is an area where things can get complicated very quickly. I do believe that your ethos of doing less, but doing it better is very wise indeed. The fact that you've NOT invested your time in lots of average, CPU hogging effects is brilliant. The two simple effects that you've implemented so far are actually the most useful I've come across in any app other than nanostudio.
At first glance, I was disappointed with the compressor as it didn't have a make-up gain knob …but after getting to grips with it, realised it didn't need one! It works differently to other compressors I've used, but I like the results. Good work! …I would however, like to see some kind of metering to show the amount of compression being applied.
The EQ is also very useful and much better than in most other apps. There are two things I'd say are holding the EQ back tho. Firstly, the high and low knobs on the left hand side need to have a sweepable frequency control rather than fixed points. If I want to put a low cut on a bass to cut out some rumble, I need to be able to do that without removing the guts from the bottom end …and the same goes for the high. Secondly, the bandwidth controls on the low and hi mids need to go much wider …I'd say twice as wide as it goes now.
10. Undo history list: It's great that you include in the menu, the name of the function to be undone. Some apps just say "undo" and you're never sure what you've actually undone! You could take this a step further to show a history list where the user could jump back say 12 levels of undo at once to that region slice they did 10 minutes ago. The list would obviously be limited by the maximum undo level, but the ability to jump several levels in one operation and also letting the user recognise their path of actions as verification they're undoing the correct things would be excellent.
11. Song loop: Would like the the blue tint that overlays the looped section to be MUCH MORE TRANSPARENT. I work a lot with looping switched on and sometimes the whole song is blue!! …This makes selecting / moving parts quite confusing. There's already good indication of the loop points in the timebar at the top of the screen.
Again, please don't think me fussy or ungreatful for all your hard work so far. It's quite the contrary. I really believe in your app and the way you seem to be developing it. That's why I've taken the time to give you some detailed (and hopefully helpful) feedback. Excellent work, I really hope this is proving successful for you guys …oh, and thank you for taking the time to read my post!

Awesome app ...Looking forward to any updates!
All the best - phormz