I'm heavily involved in IPv6 training, consultancy and deployment for customers since 2001, and recently looked into MikroTik for some customers, so let's try to clarify a bit on this topic.
There are 3 kinds of transition mechanisms:
1) Dual-Stack
2) Tunneling
3) Translation
When we started developing IPv6 and transition techniques in IETF, it was expected that we will deploy it before we run out of addresses, so Dual-stack was the way, and tunneling to transport IPv6 in IPv4 networks.
We developed NATPT as a translation to allow IPv4-only web sites to be available with IPv6, but many folks started using it in the wrong way, so it was deprecated.
On February 2011, the world run out of IPv4 addresses. So it was needed to develop new transition mechanism. Some like CGN (NAT444) aren't mean for IPv6 deployment, just for artificially extending IPv4 life, but it means several levels of NAT, which means breaking applications, not scaling, requiring further logging for legal data interception, etc., etc. You can use it together with dual-stack, but is the worst solution.
So we developed new tunneling mechanisms such as softwires (L2TP for IPv6 tunneling), DS-LITE, LW4o6, which allow to go away from IPv4, by making the ISP network IPv6-only and tunneling IPv4 in IPv6, so as more IPv6 traffic is available, less overhead. LW4o6 will be very interesting in many cases.
In many other cases we need other solutions. The one more useful for cellular networks as well as many other networks is 464XLAT, which basically is stateful NAT64 (PLAT) at the ISP side and NAT46 (CLAT) at the CPE. This allows any application, despite using "hard encoded IPv4 addresses" or using old socks/apis, etc., to work perfectly. This is being used in millions of cellular customers in US and some EU countries, probably many more in other regions. Android and Windows support this (CLAT) at their cellular OSs.
Apple has decided an alternative strategy: They mandate since June 1st 2016 (announced a 4th May 2016)), all the Apps to WORK with IPv6, which is much better, because it means they don't need to do any translation at the cellular phone (power saving, speed), but enforces the developers to recompile and some times modify their apps to support IPv6.
Another alternative, which is available in many CPEs is MAP-E (Encapsulation) or MAP-T (Translation). I think this one is better which are a kind (very very short and not "precise" explanation) of mix among 464XLAT and encoding the IPv4 address and ports into the IPv6 address. But this is not supported in mobile phones. This requires a very simple configuration at the ISP network which is called the Border Relay setup, and you basically split a given number of ports among "n" customers sharing a pool of IPv4 public addresses (while in 464XLAT all ports are available from a given IP address from a given pool of them).
So specially if you have different kind of access networks, it may be more convenient 464XLAT, unless you want to run simultaneously several transition protocols in the same "ISP core".
The code for both 464XLAT and MAP is very very very simple, and is available (source), as has been developed for OpenWRT. Many vendors are using this code for their own implementations, for example cable modems from Technicolor, etc.
Both of those mechanism, as well as DS-LITE and lw4o6, look into a future, by using only IPv6 in the access network, making this transition and coexistence very simple and making the cost much lower. As much IPv6 traffic is there, less overhead, less state in the network, etc., etc.
I think MikroTik has a unique opportunity here to include at least at the CPE side, the CLAT and the MAP code, and at the ISP side the NAT64 (stateful) and the BR function. I think it will take just a few hours, even not a complete day to do so.
Otherwise, many MikroTik customers will need to use alternatives, even using OpenWRT instead, which is not a good thing, I guess.
Hopefully this can be worked out and very very very soon.
By the way, is very wrong, and confusing, calling 6to4 to 6in4 tunnels as MikroTik is doing. Yes, they use the same encapsulation, but is a totally different type of tunnel.
