No, I don't think that adding more representatives would help the problem

I think it would. Along with creating more slots for minority candidates to get elected in. There's also the matter of the cost of lobbying. Right now lobbying is dirt cheap because you can spend a very little amount of money to influence one representative and that one vote in congress can have a huge effect. If there were more people voting in congress the value of that one person would be reduced. The lobbyist would have to work to get multiple congressmen to have the same influence which makes bribery less cost effective than it currently is.