Despite its growth and (I would assume) huge budgets going into understanding what their customers really want, the exporting dashboards and their customization elements are very hard to navigate. What I mean is that, just like everything else is optimized for simplicity, so should data visualization be as well. Perhaps a tool that you can have a look at that does a great job and is similar to Metabase is TalkBI. You simply click on one button and poof - report is made. Other than that, perhaps it would be possible to review the SQL generated by Metabase so we can help improve its effectiveness for more complex queries.