I agree the “suicide” angle doesn’t quite work for Rigg, but then it isn’t really played up all that much, either. The beach and casino scenes establish that she has a self-destructive streak, but she never really comes across as despondent or “broken” and it’s not entirely clear she’s supposed to, unlike her literary counterpart.
We “know” she’s trying to drown herself at the beach, but as filmed, is it really all that apparent? Would we know it if we hadn’t read the book? Based on what Bond sees through the scope, she could just as easily be out for a wade, or a swim, with the only “tragedy” being she’s about to ruin a nice frock. I’ve even seen someone interpret it as her trying to escape Draco’s flunkies (who remain somehow invisible to Bond, and us, until one appears out of thin air with a gun to Bond’s head).
Saving a “bird with a wing down” fits with literary Bond, who seems to picture himself as some sort of romantic hero swooping in to rescue damsels, only to fall hard for them and watch the relationship fall apart when the adventure’s over and it becomes necessary to try and maintain a real relationship in the drab light of daily reality. In taht sense, Tracy is the ultimate challenge, the most messed up of the messed up damsels, so far gone it takes a proposal to pull her out of it. But it doesn’t fit the movie Bond nearly as well (at least the pre-Roger version) as that version of Bond seems to care little if at all for the women he “saves” more or less as a side project while he completes his missions. One gets the impression with Connery that if any of the girls had been just a little more difficult or troublesome to save, he’d just as soon have left them behind to fend for themselves. So to trot out a psychologically damaged, needy, suicidal wreck like the literary Tracy in OHMSS and expect Bond to fall for her would not have worked. Arguably even less so with Lazenby, whose Bond has a more chipper, spirited attitude than Connery’s: I can’t see him going for a “Debby Downer” when he’s got his pick of so many healthy, fun-loving females to choose from.
Plus, as frought as the series already is on the “male chauvanist” front, imagine if Bond was played as the big, strong hero here to save the fragile, weak-minded female and the tragedy was not from lost love but a failure to fill the role of macho savior? There are vestiges of that intent in lines like Draco’s “she needs a man…” but it often feels like whomever it is people are discussing when she’s not around is not at all the Tracy we see played by Dame Diana. And thank goodness.