"As a fun by-product you would completely eliminate the effect of large donors on the government. Lets see the Koch brothers or George Soros donate $1 Million dollars to ~1600 Congressmen every two years."
I think that's more than a tad optimistic. If you quadruple the number of seats you also shrink the size of each district. With smaller districts the costs of campaigning would likely shrink, as would the amount each individual Congressman would need to raise.