I am of the opinion that moving to Ipv6 now would be a really, really bad idea. However, I believe things shouldn't be left stagnated. There is a saying in my country, “you don't tinker with a winning team”, that is to say, if something is working and doing it well, you shouldn't mess with it. The reason, obviously, is that you might actually make it worse instead of improving it.
So, following this logic, it would make sense to let eMule as it is and use it to the best of its capabilities. It seems logic, doesn't it?
The problem is, eMule has stopped on its tracks but things around it are moving on. The team isn't winning any more, at least not as it did before, because it is disappointing the fans and is not devising new tactics to counter the other teams' agressive moves. Why the need for so serious mods and why no requested features? Why does no one tweaks the network and the client to help root out fake files, fake clients and fake servers? There are other issues.
This is why I think things should start moving again. If compatibility is kept with prior versions or if there is support for two versions until the new version of the client/network is deemed completely safe, there would be a smooth transition, wouldn't it?
If there was a problem, we could always turn back to the earlier version and continue as we are, planning another attempt after finding out what went wrong. This version of eMule should be sacred, in a sense, and kept around in the sites for a long time, and that would be a fail safe for problems with new versions.
By the way, is it proper for me to explain here how things work in my country so you know how simple it would be to protect the servers here? I think you'd be amazed.