As far as the value of investing in the iOS app goes, I can tell you that the app is the reason why I decided to buy Accordance (hoping also for some future improvements). BibleWorks gives me all I need on the desktop, and I expect it to keep working for at least a few years. The crossgrade offer opened the prospect of mobile access to serious tools, instead of the free/cheap texts I had been using. I considered Logos, but there was no way to get the Bible translation I use on mobile: they don't sell it, and don't sync user bibles to mobile devices.
I do miss BibleWorks's easy way of comparing translations. The Logos iOS app has a compare text feature, which shows the selected verse in all (many?) available versions and highlights words that differ from the selected version (the one that was being viewed when compare text was selected). Showing the same verse in multiple translations works on any screen size, because the list can be scrolled if the versions don't all fit on the screen.
I propose this: when a verse number is selected in the iOS app, there is already a popup menu (Copy Verse, Highlight Verse, etc.). Add to this menu "Compare Translations" or something similar. Selecting it opens a new view with a back button (like Amplify). This view displays the text of the verse from each Text in the library, in the order in which they're found there. For the initial implementation, don't highlight differences, just show the text of each version. That already gets us to the BibleWorks level.
Future improvements could be up and down buttons to change verse, and highlighting differences, at least in texts in the same language.