Still working on the iPad version. At first there will not be much in term of improvement of functionality but at least the UI will be updated for the new format.
For information here is what is left for me to do:
1) finish updating the settings view
2) review all input method XIB to supress the cancel button and tweak the elements sizes
3) rotation support
4) test for regression on iPhone and older sdk
5) translate UI

Here is what was done:
1) change the Kanji view
2) change the compound view
3) embed all input methods in popover views
4) tailored handwriting input method to the iPad