It seems clear enough that the intention & expectation was for some undetermined proportion of Pro users to switch to a Premium subscription, thereby generating extra (since they would be paying again) and continuing (since now a subscription) revenue from existing customers. It is, of course, received wisdom that if you are trying to grow a business it is more cost effective to sell more to existing customers than to acquire new ones. Although it might be felt that there was some overlap between "selling" and "attempted extortion" in this case. At least subjectively: misconceived does not necessarily mean underhand.
In this context, the decision to launch an iOS version of Aqua Mail is an interesting and pertinent one. That's an expensive choice of growth strategy, involving a high up-front investment with an uncertain prospect of returns. The Apple Mail App is already good enough for most people -- certainly far better than either the Samsung or Gmail apps on Android, for example, -- so the number and type of people looking for an alternative (especially a subscription alternative) must already be quite niche. A postulation which the existing players in the App Store market for email clients seem to confirm, since they are each trying to appeal to a niche of a niche in what they offer (none of which looks especially compelling to me!) Business strategy (good or bad) has to be formulated; and then financed...
So, also in this context, it is perfectly reasonable for Pro users to be deeply offended by how they are being treated (since there is as yet no concrete resolution,) to be deeply suspicious of how they will be treated (since trust has been lost,) and to make that more broadly known to other potential users in a timely manner using the consumer power available to them through the Play Store. That's business. And sensible (since acting after the fact is too late).
If you treat a valuable resource like an exploitable resource, the resulting culture and outcomes will differ. It all comes down to choices. And value.
The fact that people are willing to post here at all means that they value something. It would be a good idea for the owners of the Aqua Mail business to properly understand what.
Then the ratings would no doubt climb again, since another bit of received business wisdom is that happy customers spread the word. That's how Apple does so well. And how Aqua Mail was able to charge so much for a Pro licence (to people who don't like subscriptions!)
