I would also like it if %g acted the same in plan9 as everywhere else (printing 0.1 instead of .1 in my example). That's also really easy to change.
It doesn't make sense for plan9port's %g to be different from plan9, because now you cannot even count on both prints to work the same way. Since printf's %g works like plan9port right now, it would make sense to change plan9's version. I don't know the history behind %g's current behaviour, however.
