Well the problem with any "redemption" story arcs is that that is meta-gaming. If you don't engage in meta-gaming, then you should be role-playing your character in the here and now, and reacting to the things your companions say and do in the here and now. And in that role-playing I don't see how a good-aligned PC can justify continuing to adventure with a vampire or a Sharan beyond the necessity of the first bit of the game. It's not like Volo comes to you tells you: Hey, don't be concerned. These companions can become nicer/good later on the game if you keep at it with them.
As for the game following FR lore, Swen himself as well as the lead writer have said on multiple occasions that the game is going to be very faithful to FR lore. So being faithful to FR lore does matter and is a valid basis for judging the game.
