Why does it say "Elokim Tzevakos"?
Radak (based on Shevu'os 35b #1): The Nismach (word that is Samuch to Tzevakos) is omitted. Tzevakos is not an adjective. We find that it is Samuch - Hashem Tzevakos, Elokei ha'Tzevakos. It is as if it says Elokei Olam ha'Tzevakos Ma'alah. The legions above go and rule in the world based on His command; He is their G-d. This is unlike those who say that they (the legions) are gods. Rather, Tzeva'os is based on Tzeva'os Yisrael. The word is Chulin; it may be erased.
Radak (based on Shevu'os 35b #2): Tzevakos may not be erased. (It seems that it is a To'ar (adjective) describing Hashem. - PF)
Why did he say "Shuv Na"?
Radak: Return to us now, and see our pressure!
Why did he say "Habet mi'Shamayim"?
Radak: Even though You are elevated and we are lowly, look at us - "Ki Ram Hashem v'Shafal Yir'eh" (138:6), "Marom v'Kadosh Eshkon v'Es Daka u'Shfal Ru'ach (Yeshayah 57:15).
Radak citing Bereishis Rabah 53: You told Avraham "Habet Na ha'Shamaimah u'Sfor ha'Kochavim" (Bereishis 15:5) - [You should] look from Shamayim!
What will be the consequence of "u'Fkod Gefen Zos"?
Radak: The pigs will no longer trample [the vine].
Malbim (16): [Establish] Yisrael [in their land], Malchus Beis David and the Beis ha'Mikdash.