If you are afraid of growth, move to Europe, or to Ohio. But remember that most of your friends are moving to Phoenix, Dallas and Miami, and they’ll have more say in future congresses.
As an Ohio resident, all I can say is "ouch."
As people move, do they change churches? Moving to a new town would (I'd guess) make people more inclined to shop for a congenial religious home than they'd be if they stayed put. That disruption is likely to hurt the traditional "mainline" denominations and help faster growing ones, since the lively churches in the sunbelt aren't likely to be the older, downtown ones but the new ones in the new suburbs. These population trends might increase the rate of decline in the older Protestant denominations and increase the shift to evangelical, nondenominational "mega-churches' which seem to thrive in the sunbelt.
This is exactally backwards. While it is true that states like Florida, Texas and Arizona will have in total a bigger say in congress. Individuals in those states will have less of a say. The two manditory Senate members for each state mean that an individual in low population state has a greater say in Congress than an individual in a large population state. The same holds for the Electoral College.