Teams don't seem to do well playing out of temporary accommodation. Every game will be almost an away fixture, and I'd expect crowd numbers to be down as well. I think we may have already seen the resulting anticipated drop in income factored into next season's signings - Saints could really have done with signing a top player along the lines of Gidley/Lyon but this hasn't happened, for the 1st time in a long while.
And then there's the irreplaceable KC.
Also, it'll be impossible to replicate the Knowsley Road atmosphere - don't underestimate the contribution of the fans!