I think that one problem is that the culture around IPv6 hasn’t yet matured enough to reflect the realities of this protocol vs. the well-worn culture of IPv4+NAT.
ISPs need to realize that changing the prefix causes undue hardship on customers with IPv6 where the public IP didn’t make nearly as much difference to the vast majority of SOHO end users.
One thing that could help in this scenario would if Mikrotik were to implement stateless IPv6 prefix translation (NAT) so that at least you could keep a consistent internal numbering scheme.
I’m generally in the “let’s abandon NAT” camp when it comes to IPv6 but unlike the purists, I have come to realize that there are certain things that can be improved by using NAT in IPv6, but like the purists, I’m worried that it will be over-used to do things that should be addressed in other ways.