My current laptop, the T450s, has full support for linux. My coworker uses a X270, which also seems to run Arch fine. I think it's just the X1 series with these issues.
Carbon is the new, fashionable, Macbook-like device with soldered-on RAM, etc; likely from a different design culture. Its biggest upside is likely the hi-res screen.
For development, a lot depends on the quality of font antialiasing and hinting, though; Linux used to provide superb font rendering in this regard.