Love this feature but I had some ideas that I borrowed from the app WeChat which also has a voice recording feature:

1) While recording if you want to cancel the recording slide your finger up
2) Some sort of way to listen to the recording immediately when you touch the wavelength icon without it opening up a new screen and then pushing the play button.

I've been an avid ChompSMS premium user, but I am loving the work you're doing with Textra. Please keep it up!