Well, he wouldn't be technically divine based on Christian standards which is all divine or no divine. I guess if you wanted to ignore legend completely and gauge it by blank sheet Nasuverse standards, you might assign him some level of divinity. The outside of heaven bit is a questionable thing imo but there's tons of ways to limit him.
1. Michael still doesn't have 100% free reign to wreak havoc and whatnot. He follows certain rules set forth as God allows Satan to do quite a bit rather than sending the angels off for constant physical war.
2. Michael is alive so no astral form.
3. Michael is going to take... how much prana to support? If its not an Einzbern master, how much he can do will be way limited.
4. Wings. Subtlety = 0. Goes hand in hand with no astral form.
So under randomized case, Michael would probably end up being substandard without the matter of advantageous placement or not. He's big, clunky, and loses out in a lot of technical ways. He's got harder upkeep, can't be recharged effectively, probably costs more than he is allowed to put out, and is obvious both in terms of being seen and his general identity being guessed.