This is the main reason why I ended up with the VL3. I would love to have midi over USB available on the new Play series devices as they are much more compact and for the most part do everything I need except midi. It's got to be possible in an update. Just have to wait it out.
I use Mainstage and a TC play electric and it would be very nice to change the preset with a programmchange (via USB and Mainstage) like I could do with the gtx. An firmware update with this feature would be great.
From what I have seen no, midi support not added yet. Not sure it will at this point. The focus seems to be on the flagship models. Still hopeful but I love the VL3 I have still. I am hoping for a deeper midi side to the next gen stuff it seems we midi users are a growing voice.
Why was it removed from the product line? (would also be welcome on the harmony stompbox version) It's not something new to be invented. Imo, it should not be something exclusively to customers who have the $$ to buy the flagship models with a lot of features they never use or prefer the smaller form factor. I don't consider MIDI input a 'bell/whistle' - feature, especially for keyboard player/vocalist who don't need the guitar stuff.