I'm wondering how many ports they are going to remove. Fingers crossed they will keep plain HDMI and not make us go back to Thunderbolt / MiniDisplayPort.
(Oh, and it'd be nice if they did something about the potential for Thunderbolt viruses...)
Something about how it handles suspend, I remember the linux kernel having massive problems too, and they don't employ the same level of power saving optimisations as Apple do.
The Surface Book had power management-related firmware weirdness for its first couple of months as well. That said, Microsoft had it fixed by ~January-February as I recall it.
(Oh, and it'd be nice if they did something about the potential for Thunderbolt viruses...)