This is the idea of one of my halakha teachers, who prefers to remain an anonymous formulator of ideas rather than a known promulgator of particular methods.
This, like R. Ner-David’s proposal in her book, involves playing with nedarim, vows. The first thing to say about vows is that they’re dangerous; there’s a pretty strong Rabbinic tendency to avoid going there if one can. They’re binding, powerful, and one wants not to be in a position where one can’t fulfill what was promised.
In any case, it does offer one way out of the kiddushin dillemma. If one violates a vow, one has committed a sin d’Oraita [of Torah law, rather than rabbinic law], so it has the same level of seriousness as traditional kiddushin. One needs to go to a beit din [legal court] to undo one’s vow–so there’s a way out, and/though it involves community consent. If a marriage ritual involves two separate vows of monogamy, care, providing economically and so forth, each party can undo his/her vow without concern for the other party. This, then, avoids some of the problems that arise if a woman wants a divorce and her husband won’t grant a get.
ADVANTAGES: Can be fully egalitarian, a solution for the get issue, is significantly legally binding, nobody gets acquired.
DISADVANTAGES: It’s not “romantic” feeling, there’s no kiddushin (as always, a pro or a con), one needs the backup of a local beit din to undo, vows are dangerous and not to be treated lightly.