I thought "The Snowmen" was an exceptionally good episode. Lots of great lines (Who would ever think the best ones would be from a Sontaran?) and the story was pleasantly silly. I always assumed gentle silliness was what makes Doctor Who so good, so I don't see why any old fan wouldn't enjoy this episode. They also made the Tardis interior look a bit simpler and therefore more like in the olden days. From where I'm standing, things are headed in the right direction.
So far, I'm more or less impartial to the new girl but I never like a new companion at first, so impartial is actually quite good. Let's give her time to prove herself before we start judging her. Also, the Doctor seems to like her, so she can't be all that bad