1) Select for each block, which module page the block should be displayed. For example, you can display 'Topics Block' only in the News module pages, 'Login Block' in all pages, 'Site Info Block' in Partners and WebLinks pages, etc.
2) Cache any block, and set the cache lifetime for each block. For example, you can set the cache time to 60 seconds for the 'Recent Discussion in the Forums' block. Or maybe you can set the cache lifetime to a much larger value for 'search block', since it normally does not get updated at all.
This should considerably lighten the load on the server, since a cached block does not need to be processed at all nor issue mysql queries to be displayed.
3) Select which block template to use for each block. For example, if there are 5 block template files in a theme, you have 5 options to choose from for each block to use as its template file.
We are still testing these features, and there may be some more changes at the time of actual release..but hope you'll like it