the reason why I explicitely disable ipv6 cause "this shit don't work" (at the moment, will probably change in the future)
- random slowdowns
- horrible routing
- larger packet overhead
- hated by a lot of the people who run the internet
- hated by companies who provide ddos protection
- my poor TCAM cache in my budget routers
- supporting ipv6 is really expensive in chassis routers
However, I believe there is a solution: Swap ISP's to IPv6 only, swap to IPv4 unless there is an IPv6 route present then directly forward. This solves quite a few issues: Once every ISP has IPv6 you can drop ipv4 and swap directly to ipv6 without having to split your TCAM. This works because IPv6 can encode IPv4 in it.