Basically Gecko is huge, roughly as big if not bigger than Wine itself. KHTML is understandable by one person. It's also more easily adapted to IEisms.
Alexandre, what's the reasoning behind the no C++ rule?
BTW: if someone follows the kfm-devel (Konqueror's) lists, then you can see that people are trying to compile it under windows...
http://lists.kde.org/?l=kfm-devel&r=1&w=2
Thanks, Hetz