Sorry, I'm still not seeing how a IPv4+ would be any less complicated (or as simple) as IPv6. In either case you would still have to:
* roll out new code everywhere
* enable the protocol on your routers
* get address block(s) assigned to you
* put those blocks into BGP
* enable the protocol on middleware boxes
* have translation boxes for new-protocol hosts talk to old-protocol-only hosts
* enable the protocol on end hosts
And just because you do it, does not mean anyone else would do in the same timeframe (or ever). You're back in the chicken-and-egg of whether servers/services do it first ("where are the clients?"), or end-devices ("where are the services?").
Redo all your addresses and routes, reconfigure or replace NAT and DHCP, reconfigure firewall, change your DNS entries at minimum. If it's a home or small business and you don't want to fight the defaults, you go from NAT to NATless.
* roll out new code everywhere
* enable the protocol on your routers
* get address block(s) assigned to you
* put those blocks into BGP
* enable the protocol on middleware boxes
* have translation boxes for new-protocol hosts talk to old-protocol-only hosts
* enable the protocol on end hosts
And just because you do it, does not mean anyone else would do in the same timeframe (or ever). You're back in the chicken-and-egg of whether servers/services do it first ("where are the clients?"), or end-devices ("where are the services?").