Michael as the restrainer is an interesting thought, and is held by many, but is not possible because of 2 Thess 2:7 which tells us the mystery of iniquity was already "at work" in the first century and is being restrained throughout this age...it is absurd to see non omnipresent Michael as that restrainer, unless it is ONLY the man of sin's manifestation that is restrained. Which it is not. The mystery of lawlessness characterizes the age (ie..it "works", while the lawless ONE is the culmination of the age long iniquity (verses nkjv)