I don't believe DBing is about improving one's self. DB stands for Divorce Busting. So the goal should be to stay married. GAL is about improving one's self and is but one tool on the DB toolkit.
I am military so I measure success by obtaining a goal. If you improve yourself but can't bust the divorce, then in my book you were not successful. That doesn't mean you are not a better person, one who has learned through this process. And you may be a success in your next R and are happier in life, but you were not successful at busting a divorce and remaining married. It's an elusive goal because You have to GAL and maybe the other person will try to engage in the R. So even if you were the best DB'er in the world you could still be unsuccessful because your spouse made the decision not to succeed for you. Boy was that a rambling paragraph.