I agree with your assessment of more detail... actually, lots more detail. However, I can see why she did it that way. She was trying to avoid a trashy novel feel, and retain her youthful (innocent) teenage audience. It was just a Gone With The Wind - <fade to black> - as Rhett carried Scarlett up the staircase.
But, gosh, sometimes I wish there was an "adult" version of the book!
Ditto on the too-many-pages devoted to Indian lore - agreed, could have been shortened. Finally, I really had no problems with the ending. Frankly, if there was a lot of slaughter, tragedy, mayhem and death, I think I would have been really disappointed.