DN 16 Mahāparinibbāna Sutta - The Great Passing, The Buddha's Last Days
"For the Blessed One, O Lord, spoke these words to me: 'I shall not come to my final passing away, Evil One, until my bhikkhus and bhikkhunis, laymen and laywomen, have come to be true disciples — wise, well disciplined, apt and learned, (knowers and) preservers of the Dhamma, living according to the Dhamma, abiding by the appropriate conduct, and having learned the Master's word, are able to expound it, preach it, proclaim it, establish it, reveal it, explain it in detail, and make it clear; until, when false teachings arise, they shall be able to refute them thoroughly and well, and to preach this convincing and liberating Dhamma.'
"And now, O Lord, bhikkhus and bhikkhunis, laymen and laywomen, have become the Blessed One's disciples in just this way. So, O Lord, let the Blessed One come to his final passing away! The time has come for the Parinibbana of the Lord."
This sutta shows that the Buddha had determined to have his Four-fold Sangha (noble disciples), including bhikkunis, fully established in the world even before he started his teaching career, and this Four-fold Sangha, including the bhikkuni order, shall be continued and developed to preserve and preach the Dhamma.
The Buddha created the bhikkuni order to better facilitate women's Dhamma practice and liberation, just as he created the bhikkhu order to facilitate men's practice. This led me to believe that bhikkuni should be the best vehicle for women's liberation, instead of 8- or 10-precept nun and etc. As followers of the Buddha, we should put faith in him and try to revive the bhikkuni order so that his Four-fold Sangha will be fully established again and continue to thrive in the world.
Metta to all!