Yeah. Definitely agreed, there. There is such a thing as straying too far from the original.. so far that you lose almost everything that made the series enjoyable in the first place.  
no, I disagree... I think if a universe is fleshed out well enough, you can tell all sorts of stories without having to reference the original plot/characters.  
 True, but I was referring more to the loss of critical elements that make the series successful to begin with. Improvements are fine. A certain amount of reinvention is also necessary, to a point. Otherwise things get stale. But as far as the critical elements are concerned... 
.. if it ain't broke, don't fix it.