It's nice to get a pass, and it would be even nicer to get the result for each domain. That way, I would have a good indication as to whether I should be pursuing a concentration in the case of CISSP, and which areas I need to brush up on (those where I just made it).
Re: Why don't we get a detailed score when passing?
I believe they did used to provide the score on passing or failing a long time ago. More recently you would only be given your score if you failed.
However, these days (seemingly when the CISSP CAT version was introduced) if you pass any ISC2 exam you just get told you passed, and if you fail you get given a breakdown of proficiency level per domain - proficiency levels being above, near or below, with the view being to advise you of the areas where you need more work.
I believe they stopped giving the scores when you passed to stop people from comparing members based on their scores. e.g. If you scored 1,000 (the maximum) you were considered better than someone who scored 700 (the minimum) as ultimately the view is a pass is a pass.
Inevitably though, some people like to compare themselves, so after scores stopped being provided, the measure was how quickly you completed the exam, and with the CISSP CAT version how few questions you received, but such is life and human nature... ¯\_(ツ)_/¯
Whether ISC2 would want to publish proficiency levels for passes I suspect this won't happen, as even though it may be helpful to the test taker in some circumstances, it would lead to the same kind of comparisons they want to avoid. e.g. Someone who was above proficiency in all domains being considered better than someone who was above proficiency in 6 out of 8 or whatever.
In terms of choosing whether or not to pursue a CISSP Concentration based on domain proficiency levels in your CISSP exam, you probably already have a feeling for the areas in which you'd like to gain a deeper understanding based on your interests or career aspirations, so I think that is a better barometer to use to guide your choice. After all, there could be many reasons why you didn't do as well you'd like in a particular domain in an exam, but deeper study in that domain would still be a better choice for you in the long run.