What are the ramifications of "ve'Lo Kam Navi Od be'Yisrael ke'Moshe"?
Seforno: That is why no Navi has the authority to issue new rulings that are not contained in the Torah. 1
Toras Moshe (on Pasuk 9): No other Navi could ask Hashem Divrei Torah. Also refer to 30:12:1:2 and the note there.
Da'as Zekenim and Rosh: Before Moshe died, he asked Hashem to open all gates, so all will see that He is alone. "V'Yadata
What is the meaning of "asher Yeda'o Hashem Panim el Panim"?
Ramban #1: It means that Hashem raised 4 Moshe above all the other Nevi'im by speaking with him face-to-face.
Ramban #3 (according to Kabalah): 'Hashem knew him face to face, to [let Moshe] cleave to Him whenever a spirit (of prophecy) entered into him - as occurred at Matan Torah. 7 And the Pasuk is now informing us that Moshe's prophesies remained on that level each time he prophesied. 8
Seforno: It means that whenever Hashem spoke with Moshe, the latter remained in control of his faculties. 9
Targum Onkelos: To whom Hashem revealed Himself face to face.
Targum Yonasan: Whom the word of Hashem knew 'word upon word'.
Rosh: Most Nevi'im, their prophecies concerned individuals, e.g. Eliyahu told the Tzarfatis that the oil and flour will last during the famine, and Elisha told the widow to borrow Kelim covertly. All Moshe's acts were for Yisrael, and for all generations, and in the eyes of all Yisrael. 10
See Sifsei Chachamim.
The Pasuk actually writes that 'Hashem was familiar with him'. See Ramban.
Ramban: Refer to 34:10:2:1**. The Torah did not write specifically that Moshe knew Hashem in deference to Hashem.
Ramban: Even though we find the same expression used regarding Yisrael in Devarim 5:4. See Ramban.
Ramban: The people however, only heard the Voice that came from the fire. See Ramban, who elaborates.
Ramban: Whereas with regard to all other prophets, the Hand of Hashem was upon them.
See Seforno, who describes the uniqueness of a Navi and elaborates on the 'knowledge of Hashem', based on the Rambam in Hilchos Yesodei ha'Torah, 2:10.
Bamidbar Rabah (14:2) expounds 'there was no Navi in Yisrael like Moshe, but there was among the nations, i.e. Bil'am.' How can Bil'am be compared to Moshe?!
Sefer ha"Ikarim (3:20): Just like Moshe's [level of] prophecy was for the sake of Yisrael (and when Yisrael sinned, Hashem told him "Lech Red"