Something like the Fender Smolder. Most overdrive and distortion pedals and amplifiers for electric guitar assume a speaker cabinet down the signal chain. Cabs filter away a lot of top-end. Acoustic signals are much readier for prime time out of the box, so they are usually sent to FRFRs instead of guitar cabs, with a lot of bottom- and top-end. So, when trying to add dirt to an acoustic signal, you either end up making it sound like an electric guitar by adding a cab, or you end up with an unusably harsh, bees-in-a-jar type of tone.
After much tweaking with pre- and post-EQ, acoustic IRs, and dry/wet signal blending, I managed to achieve decent breakup/crunch tones in the QC for a piezo-equipped guitar. However, trying a couple of captures of the Smolder immediately improved the tone in a significant way. This is a pedal that is designed from the ground up to flatter acoustic guitar tones, with proper treatment of the massive lows and highs in those signals to avoid mushy boominess and top-end harshness. As a bonus, it also sounds great for electric guitars! It also has lots of options, not least of them is the blend knob, which makes static captures insufficient to cover all the ground available.
This is something people have a clear need for and, together with acoustic body response blocks, would make for an irresistible package for acoustic players.