Mixed Blood

[Morthoron]

Originally Posted by Mithadan

Elros' decision bound him and his offspring. I have always believed that the decisions of Elrond, Earendil and Elwing were also binding upon their offspring and that Arwen, by choosing to remain in Middle Earth, did not change her fate.

Your logic is flawed, per Tolkien. In Letter #153 he states:

Elrond chose to be among the Elves. His children -- with a renewed Elvish strain, since their mother was Celebrian dtr, of Galadriel -- have to make their choices.

And then later in the same letter:

When she [Arwen] weds Aragorn...she 'makes the choice of Luthien', so the grief of her parting from Elrond is specially poignant.

Elrond's children unequivocally had to make their own choices, and Arwen was sundered from the Elves forever (like Luthien). The differentiation from Tolkien for Elrond's children (as opposed to Elros' children, or later, Imrazor's children) is that a renewed strain of Elvishness was the determining factor in 'the choice'. This is obviously consistent, as none of Elros or Imrazor's children had any further Elvish mates, and though they retained a longevity greater than regular mortals (and even in some cases 'elvish appearance', as noted by Legolas), they did not have the special circumstances required for having to make a choice.