I finally have a solution that works for the kill the convoy leader bug
When you kill the leader of a convoy there is some chance (not sure what the percentage is or what causes it to happen - it's definitely a game C++ code bug though) that the next leader will inherit the role of the previous leader and all ships in the group will keep their previous assigned roles. This is bad, very bad
Reason being because the new leader is then unable to assign new tactics or roles. To counteract this problem I set an error tactic and then basically let each ship act independantly of the group. I wouldn't call it elegant but it does get the job done
Many, many hours of testing went into figuring this out and finding a solution
There are times when this bug doesn't rear it's ugly head and the new leader doesn't inherit the previous leader's role and thus it is able to assign new tactics and roles as needed. When that happens I do not set an error tactic but rather just let the new leader do as it pleases.
Now I just have to finish up the merchant leader tactics and v0.0.22 should be ready for release
EDIT:
actually I'll let v0.0.22 release as is so I can get many people testing the new changes and fixes. The finishing up of merchant tactics I'll do in v0.0.23