Non-standard software stack (=no udev, DBus, X, init.d, the whole sh*t thats necessary), which makes porting FOSS software a nightmare. And i'm not satisfied with feature-restricted but oh so elegantly web-style developed crapps relying on >60px sized buttons.

One example: look at webOS. Luna is the system / app / framebuffer manager, whatever, here. Installing a JS-based(!) patch? Restart it, or even reboot. Compiled-in keyboard layouts? Yes please! (patchable in a limited way but still crap)
System takes ages to boot and it's not even doing half the work that Arch is doing when installed natively.