The Lippe-Detmold question in our timeline, is a now obscure dynastic squabble involving the succession in a constituent state of the German Empire - further information can be found in the Wikinfo article.
Timelines to be developed:
1) Variant successions - some of which led to Wilhelm acquiring increasing direct or indirect influence and control over components of the German Empire and succession disputes - there were other potential cases.
2) This leads to a more coherent Germany, affecting the lead up to World War I.
3) Alternatively, the rulers of the various components of the German Empire (or administrative bodies thereof) see Wilhelm's activities as an actual threat, and set in motion processes to curtail his authority/potential for interference. This effectively leads to a less aggressive Germany, with less interest in/capacity to fight in World War I. Even if WWI occurs, a more federal entity will lead to a different postwar political climate.
4) The Federal Council of the German Empire became, in the jargon phrase, a more pro-active body and declared it had a part to play in the activities of the Empire as a whole and between its components. The sources of power within the Empire thus change.