As discussed many times in the community trying to dump all the information on the single dashboard will always be a burden on the performance. 50 web service all you can do it to manage which one to refresh first or later may be at the time of invoking rest of them later at the navigation. Nothing can be done with the 580 component to load with the data.
>Use "show loading status" from file menu.
>Load Time= BW Query Processing + Flash loading/initialization + Web Service + Flash processing
As a best option try to explain the client or the team to break the analysis into different dashboard or try to do the analysis in the aggregated level not on the detailed level.
