But OTOH I fear updates because above all I don't AquaMail to become bloatware.
I am a bit more conservative in my needs, and I am mostly happy with what I have now.
The major functionality that is missing for me at the moment is the per-account configuration of sync on mobile networks. And once it will be implemented (I am hopeful), and I switch to that version, the only missing thing would be the recently removed reflow-on-zoom.
(And I am hoping that no other valuable (for me) existing functions will be removed in the mean time.)
My experience is that Kostya has been rather conservative about not turning Aquamail into a bloatware. I cannot speak for the MobiSystems' policy, but so far it sounds like they have been listening to his opinion, trusting his vision that brought the app to where it is now. So the fact that Kostya remains the "chief" developer, is a positive indication.
And I've seen Kostya being very conscious about not making Aquamail a resource hog. I remember when he was deciding how to implement conversations (threads), the app size was carefully considered (and a couple of very different solution options were compared).