Dear @lubos,
I know that since the introduction of the latest version of Custom Reports and of Transformation getting info from Manager is a lot better but it is still far from satisfactory, at list from my needs point of view.
I think that the main problem is that creating from scratch a satisfactory reporting tools is almost impossible and it will take a long time.
All that said, I propose to integrate Manager with an open source BI solution (I would suggest metabase.com) and give users the freedom the finally have access and use our data.