No, it's not. It creates a system of haves and have-nots. If that's the norm in a society, some men will have lots of wives and many others will not have one at all. Because of the nature of the genders, a woman marrying multiple husbands would be as rare as homosexuality is.
It would also seem likely that the children would be spending disproportionate time with the mother as compared to the father. Not to mention each wife would not be able to receive the same amount of attention from the husband as they would in a monogamous relationship. It doesn't sound like a healthy model at all. Sure you can find examples where everyone in such a relationship says it's okay, but you can find homosexuals who say the same thing. Even if it works in some odd cases, that doesn't mean it's the right model for society.
Homo “marriage” is nothing like those because it cannot fulfill the fundamental function of all marriage, the proper raising of children who REQUIRE a mother AND a father for proper development.
Monogamous marriage is the worldwide norm even in countries that allow polgamy and it is superior to the other two natural forms. As you say women and children get more attention from the father. While it's true that women in polygamous societies are second class citizens, children are properly raised, the societies themselves perpetuate themselves and are stable.
This is why I say Polygamy is a step up from Homo “marriage” because in no way can you connect the unnatural behavior of homosexuals in a “committed” relationship to real marriages of whatever kind. Destructive behavior doesn't cluster with normal constructive behavior no matter how much anyone may want it to.