The Statement section's statements take up a lot of space. This means that it can take a lot of time to scroll to other sections below like Identifiers and Interwiki links for items that have many statements.
For example, see Q30.
It should be able to be minimized/collapsable like this image. This could be done by placing a button next to the section header that collapses all of the section's contents.
Similarly, the other sections should be collapsable.
Discussions on Wikidata:
http://www.wikidata.org/wiki/Wikidata:Project_chat/Archive/2013/06#minimizing_Item.27s_UI