In book seven, how might the impression Odysseus and we receive of Phaeacia be significant for Odysseus' subsequent return to Ithaca?
This is a great question and there will be many possible answers. It really depends on a person's perspective and interpretation of the text. One the odd curiosity of King Alcinous and the Phaeacians is their propensity to forget. They are a people who do their own thing with little worry about what is going on in the world. In a word, they live in their own world.
If we dwell on this hermetic and forgetful mentality, then we can say that these are direct challenges to Odyssey. He has fought a long war and he has been a sea for a long time. His homecoming has been delayed and fraught with so many hardships that the easiest thing for him to do is to forget about it all. Forget about his past life and simply settle. The temptation is even greater, because king Alcinous does offer his daughter's hand in marriage.
To Odyssey's credit, he resists and he leaves with the help of the Phaeacians.