I'm not sure where you feel Christian tradition states that we are allowed more than one wife. I've never heard this one before.
As for Jacob, his wives drove him crazy. So did his sons. The twelve tribes (and they were begat by Jacob's two wives and two handmaidens) had numerous problems. His sons sold Joseph into captivity hoping never to see him again, others tricked people into circumcision and then murdered them, and Judah refused to do his family duties to Tamar yet he was willing to "sleep around". As a whole the tribe of Benjamin wasn't any better than Sodom and God virtually wiped them out (Judges 19). As soon as Solomon died the northern ten tribes were off worshiping not one but two golden calves. You'll find it difficult to argue about how wonderful the twelve tribes were.
The only reason a person wants more than one wife is for the same reason a person wants four/five cars, 2, 3 or 4 homes, the latest and greatest HDTV home theater system or anything else; lust and greed. The Bible doesn't explicitly condemn polygamy but it is implicitly implied you should only have one wife. The sacraments were never denied to a member with more than one wife but people were encouraged to only have one.
God created Adam and Eve. He didn't create Adam and Eve and Barbara and Clair and Susie and ... One was all that Adam could handle-and then he didn't handle her very well.
Something very strange is going on at this site. Last week there were some alleged Christians promoting euthanasia and bashing other Christians for speaking out against it. Now it's polygamy. Something very weird is going on here. It could be the common selective Christianity according to one's perversions or something more unholy on a large scale. Either way it's disturbing.