From what I understand, it's less a matter of making a colour screen for that chip (actually, the whole board) as it is making a C generation DNA250, as colour is only a tiny part of the difference. It has a more powerful processor and much more memory, for a start, and of course an additional "select" micro-switch, with whatever additional circuitry is required on board and chips to make use of it.
So making a 250w version of the DNA75 is far closer to what would be necessary - and much easier to do, as it just means adding the increased power capacity and balanced charging aspects of the 250 to the DNA75C.
And yes, I think done that way around, it's almost inevitable that there is something in the works, although there is no way on earth you'd get anyone at Evolv to admit to it, except maybe under very strict NDA terms. They'll announce whatever they are working on when it's ready, and not before. We can be sure that the hardware team are not sitting on their hands while the software team work on porting EScribe to Mac (and hopefully, Linux).
It won't be simple (or everyone would be doing it). Even at the 90% efficiency level (which is good for this type of device) you still have to find a way for the board to dispose of a ninth of the heat the atomiser does, but almost or completely without ventilation, and board area isn't exactly plentiful either. Given the popularity of 2 cell mods we may even see a board with 150-170w output first, as even that is a considerable saving in heat dissipation requirement and one less pin (and associated PCB track) for the charge balancer (which isn't needed at all on the 75w version). Given that DNAs suspend charging when you vape in "pass-through", I don't think I'd be going out on much of a limb to guess that heat dissipation is the largest part of the problem - why else would you suspend an additional perfectly good source of power right at the time when the user would most want it and the cells would have their load relieved by an amp or two?
Nothing I've said goes beyond what you could call "informed speculation" or educated guesswork, but I think it all makes sense - I don't believe the market would stand for cooling fans, so the board must dispose of all the power it uses (which all turns into heat) by whatever trivial level of convection is available and by using the wiring and stand-offs as heat-sinks. Not that you'll get rid of much heat through the wires going to the 510 connection, as it's more likely to be flowing the other way.
