It would be nice to have an option to output Fuyin Zhuhao when typing in pinyin.
I'm not sure if it would be better to make this its own inputengine, or to incorporate it into the existing checked/free inputengines. If it was standalone, it would probably also make sense to have checked/free versions, which might end up duplicating a lot of code.
Incorporating it into the existing engines would add complexity to the code, and might also require a redesign of CompositionString (which might need to happen anyway to implement this).
It would also need its own button on the toolbar.