My personal opinion is the engine should be decoupled from the GUI and built as a library to allow for easier upgrades. But don't quote me on that I'm not a developer.
If you take a look at the Odyssey code base, the actual GUI part is really quite tiny compared to everything else.
Anybody who manages to get to the point of running Webkit in "minibrowser" mode with a dumb window output on AROS should find it relatively trivial to add a basic native user interface.
Besides, it does not necessarily make the updates easier because regularly rewriting your "abstraction layer", which would sit between your GUI and Webkit, would not always take less time compared to just adapting your GUI code that might directly call certain Webkit functions otherwise.
The real problem is that Webkit is a giant project that is constantly changing and its developers do break things quite frequently. There is no easy solution. It simply takes effort to deal with that. There are no shortcuts - except for using the work that somebody else is already doing maybe...