I've had little to no problems with the callbacks to the previous titles. I'm the type of player to read the description of every item I pick up, whether it be something as insignificant as Rubbish or Dung Pie or as seemingly important as the items you gain from defeating bosses, and the majority of references that have been made have had some kind of lore-based justification.
In terms of DS3 being able to stand on its own merit, I believe that it does. Similar to The Witcher 3, I believe that the game stands perfectly well on its own merits but those that have invested time in the series's previous titles will have a comparatively enhanced experience.
As you've said, still early days, I could be wrong. However, as of right now, that's where I stand.
@nightriff: For me, it doesn't come close to the LotR trilogy and falls short of the first Hobbit film.
BOTFA is my least favourite film of the Middle Earth saga. Aside from some good performances, from Martin Freeman and Richard Armitage in particular, the whole film felt underwhelming and even annoying at times. Jackson dun goof'd in my eyes and it's a damn shame.