By drawing district lines around politically homogenous populations, gerrymandering guarantees that representatives accurately represent the views of their constituents and enables hyper-partisan behavior without consequences. Adding representatives does nothing to change that. 6400 gerrymandered districts will give us the same results as 435.
My back of the envelope math gives the US 6400 member of the house at the current population which also has the effect of reducing each single member's importance.