I'd like to revisit the topic of what, if anything, is wrong with polygamy in general.
For the sake of argument, let's imagine for a moment that the practice of polygyny, or polygamy in any form for that matter, had no religious consequences whatsoever. Imagine that it was never a matter of obedience to God and never a sin. No threat of damnation either way. God creates the Earth and says, "It's up to you; you can have as many or as few wives as you want, I really don't care either way."
I think we can find out a lot about the rightness or wrongness of polygamy by considering it in this way. The question is, what kind of people would choose monogamy or polygamy and for what reasons?
I read an article a while ago written by a woman who was in a polyamorous relationship. She had met a man and they had fallen in love, but somehow also met a woman who was attracted to her boyfriend. The women became friends and the boyfriend had feelings for both, so they all agreed that they would not compete for affection. They eventually all met some other people, got along very well, and all moved into the same house, some married others, but only for legal benefits. They all dated amongst each other and some had children with one or several of the partners. These people all loved the setup. They had consciously made the decision to share those they loved with their friends.
Maybe what worked about this scenario and makes it seem okay to me is that they all made a choice. No one was threatened with damnation if they didn't do it, but it was what they wanted, so they sought it out and it worked for them.
I suppose if this had been the situation in the early days of the Church, I might feel differently about polygamy. If the choice had been up to the members, with no promises of eternal punishment either way, I would hesitate to condemn the practice. After all, just because it's not my cup of tea doesn't mean I am the ultimate moral judge.
Naturally, each member still had a choice. No one put a gun to Helen Kimball's head to marry Joseph Smith. But where I must make a moral criticism is the fact that her ability to make a safe choice with equal consequences was all but robbed from her when Smith told her that the salvation of her entire family depended upon her decision. So it could be argued that she did choose to be his 26th (give or take) wife, but I would counter that her actual choice was severely diminished.
Now, back to the question; What kind of person would choose polygamy if it were not a commandment from God? Historically it has been men who are rich, who treat women more as property than people, who desire several sexual partners more than emotionally intimate relationships, whose first wives cannot produce children, whose first wives are not as sexually interesting anymore, who want to spread their kinship ties to several other families by means other than betrothing their children, and sometimes who feel it necessary to support women who would otherwise not have the option of monogamy (click here and here for some interesting views on polygyny and economics). A woman might also choose polygyny over monogamy if she preferred her privacy, wanted children but not necessarily her husband too close to her, had no issues with jealousy, could not have children otherwise, or who needed financial support she could not otherwise have, and perhaps who decided that fidelity was not a requirement for trust.
Imagine then, what kind of person would choose monogamy over polygyny? Naturally, a man who could not afford more than one wife. But let us consider the pros and cons of one over the other when all things are made financially and religiously equal. A woman might choose monogamy who wanted equal partnership between husband and wife, a husband dedicated to her and her children more than anyone else's, emotional and physical intimacy from the same individual, who desired a strong and present father figure for her children. In short, a woman who does not want to share her spouse (call it selfish or self-respect, however you interpret). A man might choose one wife over several because he wants no one else - his first wife is maybe not perfect but at least close enough, he is too shy of other women, his first wife is the only woman who could love him, he wants children to whom he can be emotionally and proximally close as much as possible, he wants to invest his romantic and companionate love in one single individual, he respects his wife's feelings, wants her happiness above his own, and he would do nothing to harm her self-esteem.
Admittedly, these are my own thoughts about plural marriage and monogamy. Anyone reading this who disagrees is welcome to argue their case. In brief, it seems to me that polygyny has more to do with sex and money while diminishing love and respect. Monogamy has more to do with unity and trust.
Of course, the end argument from the LDS church is that "God commanded it, so any discussion is irrelevant". That is not fact, however; it is only interpretation. The fact is that Joseph Smith said God commanded it. That does not make it so; that only should focus the attention on Joseph Smith's credibility. I argue that while a perfect god may ask us to do things we do not want to do, he would never ask us to do things that are contrary to conscience and destructive of human relations with no clear benefit.
Could it be that the threat of damnation from God was the only thing that got most of these women to consent to become plural wives? What an odd act from the most perfectly loving being in the universe!