Fluffy bunnies.
I think increasing the House would give third parties the opportunity to be represented. I think is a good thing. I don't agree with sf about third parties. I think the two party system stifles these additional voices from gaining any legitimacy. That being said, I don't think increasing the House will make Congress more efficient--and that is my main objection to any radical increase.
As for the old boy network, a small increase keeps the old boy network alive, but a radical increase at one time, would give opportunity to some new boys.