If one Eve ruined the creation, a host of them couldn't have done any worse!
I think a huge part of the problem on this discussion is that most participants view the Bible through American eyes.
Most of us don't understand squat about mideastern culture or custom and readily spread that ignorance and misunderstanding around to others!
Covenant of salt, hospitality, blood oathes, foot washings are all fairly uncommon to Americans. Why should the idea of multiple wives be any different?