Games Asylum: “One of the reasons weve never been treated to another South Park movie is because any ideas surrounding new plotlines and fresh directions are fed back into the series itself its a beast that needs to consume, as Matt and Trey once put it. This stance applies to South Park video games too, with Ubisofts two RPGs devouring ideas that could be used for a movies premise.”
Source: N4G PC South Park: Snow Day! review – Games Asylum