Ergodox is essentially still flat in design. It should at least be curved in shape, or have a palm rest like the Nostromo.
It would have been more difficult to engineer the ErgoDox to be curved like the Kinesis. I have tried and could not find a good, affordable way to do it for a DIY keyboard. Kinesis' key wells (like a plate) are injection moulded plastic, which requires an expensive mould to be made, with the cost divided over a large amount of keyboards. It also has an unusual curved PCB behind the switches.
With ErgoDox, all you need is basically an ordinary PCB with the components on it - the plate is actually optional (or rather, it was supposed to be).
One thing I think improves the ErgoDox, making it only slightly more curved, is to use Cherry profile keycaps for the main keys and OEM profile keycaps for the pinky columns, the OEM keycaps being about 1 1/2 mm higher.
There
are ErgoDox'es with integrated palm rests. Some kits through Massdrop, others that people have built themselves. There is at least one guy that has broken off the thumb keys to put them at an angle, more like the Nostromo.
It is a DIY keyboard, and it is an open design. It itself was based on the Key64, and it has inspired several others.
BTW. Kinesis has been known to sell separate replacement key wells. Maybe you could build your own based on them. You would still have to provide the thumb keys, etc.