I suppose if I had done it myself, I would have had the Flight to the Ford stay the same as the book (generally, although I don't mind nearly as much as most people the way PJ did it), and would have included the feast scene where Frodo first sees Arwen. I would have had the same feeling as when PJ intros Arwen (ethereal music, come hither look, glow, whatever), and would have kept the love scene on the bridge the same, including their exchange in the shrine. I would have included a flashback scene in Lothlorien, perhaps w/ Galadriel and Aragorn talking or something, to dramatize when they first met.
In TTT, I would have skipped their whole spat, but I would have included her scene w/ Elrond, although I would have changed it so that it was a different tone and changed the dialogue. I would have kept in the part where he thinks of their conversation (the first flashback scene), but again I would have done things a little differently (ie, camera angles
-- ooh, I could see a nice shot from above, and a breeze blows through and mingles her hair w/ his. Or from the side, a profile of the two of them, as they look down, and then look up into each other's eyes.)
Just my quick thoughts.