I don't necessarily know what JJJ practitioners are like, and I agree that every will specialise....they will tend toward their own favourite techniques.
I just believe training to stop someone with strikes can be done.
I think you should be trained for all types of fighting though. But I know what you mean by the master of none...the style I do is really only 5 basic strikes...then you learn to vary them.
Wisdom is better than rubies and all the things that may be desired are not to be compared to it