I don't think Midi (through the din connector) has improved or changed much since its inception. Instruments that use midi have simply started to take advantage of the unused controller data that was left fallow for many many years. Truly advanced guitar synth products have completely sidestepped midi altogether to avoid its relatively low speed. It's fine for triggering sampled instruments telling the instrument which sample to play at what velocity, channel, duration and what controllers are being sent. Get too many of those controllers going to the instrument and the whole transmission system bogs down. So even if some new keyboard is capable of receiving lots of control messages to make it more expressive, midi itself throws a wrench in the works. I do wonder what trickery Seaboard is using on their instruments to make them to be so expressive. The Roli Seaboard instruments are not normal midi instruments though. I'm not sure they even have midi ports - just USB.
As for the Helix and technologies like it, I don't think it's all that easy to map out and replicate ALL of the tactile things that happen between a guitar and an amp. I think it is still a "work in progress". I gotta say though, I recently got a NuX MG30 and right out of the box, its tactile response feels better than the Helix. I liked the Fender, Vox, Marshall and Dr. Z models immediately with very minimal tweaking. I'm getting bright but non-fizzy amp sounds that I didn't really have to work too hard to get. It's giving me some of the sounds that I've been struggling to get from the Helix. I find its EQs and compressors more effective and its effects more pleasant to hear.
I'm keeping the Helix because it still does things that the MG30 can't at its price range and size limits. But if NuX builds something akin to the Helix in size and capability...
I'm not saying this last bit to cause trouble. This is simply my current experience.