I have a suggestion. This wallet should add the ability to import your own addresses which would have been generated out of this client. This would prove to be useful for the people that have generated their vanity addresses but they would not be able to import it in MultiBit HD.
That would mean that you wouldn't be able to recover your bitcoin, in extremis, from your wallet words as the wallet would no longer be fully deterministic. As MultiBit HD is targeted for new users of bitcoin we (Gary and I) decided to keep this wallet fully deterministic.