How to make the move?
My ISP (Plusnet) is IPv4 only.
I run a number of different IPv4 RFC 1918 subnets at home on different vLANs and/or WiFi SSIDs (as I used to for my work). I have a 'services' subnet for things like e-mail, LDAP (VM) servers, I have a 'Home Entertainments' subnet, a 'Guest' subnet (for visitors' phones etc) and a 'DMZ' for world accessible services like web, XMPP and IMAP. Part of the security of the set up is that servers in the DMZ can only reach the 'services' network through my pfsense firewall ruleset.
Sure I could turn on IPv6 for all this kit and I could use my Hurricane Electric IPv6 address block and assign routeable addresses to everything I need to - but unless I subnet my IPv6 block to mimic my internal IPv4 setup I effectively 'flatten' my carefully built multi-vLAN configuration. If I have to mimic the subnetting to achieve the same control over routing and packet filtering then there is little advantage to enabling IPv6 - apart from self-education and being ready to turn off IPv4 eventually...
As far as I can see, there are two ways way for a business network to move to IPv6:
1) subnet their address space to mimic IPv4 which seems like a lot of effort to achieve the status quo.
2) rip and replace.
There would have to be a major benefit to risk option 2 IMO.
Whatever you want (sorry - if you've now got an ear-worm).