ADC functionality has been a much requested feature, good to see it has become reality with the DAC+ ADC boards.
What I am missing in the portfolio though is a board with analog inputs and digital outputs.
For customers people (like me) that only listen to streaming or vinyl you could consider developing an add-on board that'll give you a phono preamp.
The use case is quite simple: I am mostly listening to digital streaming audio through an external DAC (connected to my HiFiBerry Digi+ Transformer Version). Every now and then I become sentimental and feel like listening to my vinyl records - but since my DAC (with digi in's only) is also my preamp directly connected to my Hypex amps I repeatedly ask myself: Where are the phono preamps with digital outputs?! I believe Pro-Ject had a product once, I know Linn has something for their LP12, Thorens have their MM 008 ADC, PS Audio has the NuWave Phono Converter, but to make it short: there's nothing in the "affordable" range and there's certainly nothing in a RPI HAT format afaik.
Since I know that you (Daniel) have been fiddling around with phono preamps in the past, why don't you just open that drawer with the comfortINA plans again and make it happen? (:
I am sure many others would be interested in either listening to streaming digital audio followed by vinyl with just a mouseclick - or just use an RPI to digitize their vinyl collection.