Its a particularly tricky job for ppc and 68k systems given that WebKit sources more or less favor little endian systems.
This is a big part of the reason x86 AROS Odyssey is more advanced than the versions available for the other NG Amiga based systems. Fewer obstacles for the developers.
Granted WebKit isn't the only option, but its the best option we have for for a modern, bells and whistles browser engine.