Well if you're going for a vote/interest feeler for an ArmA 3 Campaign then I am in! Since I wasn't too familiar with creating my own missions (and I really wanted to do the training Campaign) I took the liberty of unpacking the mission PBO and editing it to use ArmA 3 default classes/items. I've gotten a pretty good working copy. If you want, I can send it to you to review and then you can probably push it out to others that want a working ArmA 3 Training Campaign. I didn't get a chance to do the others, hence they are untouched and still reference Arma 2 classes.
Regards,
Rico