To begin with, Snorri's Edda, the Prose Edda, is prefaced by a somewhat long-winded account of the beginning of man-- that is, the Christian Account of that evolution, and ultimately how it led to the men who would later be considered gods to the Norse people. Adam and Eve, Noah's Ark, the Great Flood, even King Priam of Troy get mentions. Snorri doesn't hide his agenda. In one respect, this makes it a lot easier to sift through. We know Snorri is writing from a Christian Worldview, and it's quite clear that he means to discount the divinity of the gods in order to preserve that theology.
For instance, in the prologue Snorri places Thor quite firmly into human history as a grandson of King Priam:
One king among them was called Múnón or Mennón; and he was wedded to the daughter of the High King Priam, her who was called Tróán; they had a child named Trór, whom we call Thor.and turns Sif into Sibil the prophetess:
In the northern half of his kingdom he [Thor] found the prophetess that is called Síbil, whom we call Sif, and wedded her. The lineage of Sif I cannot tell; she was fairest of all women, and her hair was like gold.
Oh so very Greek of him, and a testament too, to the pervasive nature of the mythic Troy* and it's people as a fact of history, cross culture. He also goes on to make Odin a descendent of Thor, and leader of an exodus to the Northlands:
Odin had second sight, and his wife [Frigg] also; and from their foreknowledge he found that his name should be exalted in the northern part of the world and glorified above the fame of all other kings. Therefore, he made ready to journey out of Turkland, and was accompanied by a great multitude of people, young folk and old, men and women; and they had with them much goods of great price. And wherever they went over the lands of the earth, many glorious things were spoken of them, so that they were held more like gods than men.
To say this is a far cry from the Norse creation myth** is an understatement. But it serves his purpose-- turning gods back into men, historical figures who can then be explained by gossip and boasting pre-vikings. I can certainly appreciate his translation of Aesir into a term referring to men from Asia, as in men descended of the House of Priam from Troy, though his supposition that they brought with them the language from Asia has, as far as I know, no linguistic basis whatsoever. It is, however, rather creative of him.
But this is what Snorri DOES; he rationalizes the mythology of his people to something which can fit within the Christian theology without competing against it. Suggesting that these gods were not gods at all, but men who have been honored and revered to the point where we forgot they were just men allowed a certain amount of preservation, even if it leaves us with a lot of teases and a source of questionable reliability.
On the one hand, we should be grateful to Snorri for preserving even as much as he did. On the other hand, I would give my left arm for a textual source written down before contact with the Christians and the conversion of the Norse people to that new faith. To hear the stories of the Norse gods from someone who honestly believed in them, knew them for allies, and placed him/herself in their hands, would be an incredible gift to our understanding. Snorri, though, is not it.
*The influence of Homer is pretty astounding when you think about it-- this Edda was written around 1200 AD, and Homer's Iliad was at earliest recorded ~700 BCE. That's almost 2000 years later, and don't forget that Snorri is also an Icelander! That's a long way in time and physical distance for the Epics of Homer and the ancient Greeks to travel.
**Odin, a son of Bor, himself a son of Buri who was licked from the ice by the cow Audhumla, and thereby the father of all other gods--and Thor the son of Odin after Odin and his brothers slew Ymir, the giant of all giants, and formed from Ymir's body, blood and bones the mountains, rivers, seas, etc. that make up our world.