@Schrammy: Thank you for helping with real facts.
@democracy/constitutional monarchy:
I think this is a problem of definition. Monarchy refers to the head of state. That would still be the Kaiser in 1918. As far as I know, a constitutional monarchy means that the monarch is still at parts the souvereign, but has to share power with the people. In most cases, as in France and in Germany, that meant that the monarch was the executive branch and had to work together with a elected legislative branch. this is the basic model, then there might be a right to Veto against laws for the monarch or the only right to appoint a government, whatever. Thus, Germany was a constitutional monarchy, but with very restricted democratic elements.
Parliamentaric monarchy refers to the British system, where the parliament elects the government and the monarch has only representative functions or very limited political power.
Of course, Germany would stay a monarchy. But it could get more democratic. Maybe Prussia quits its election-system of three classes, maybe the Reichstag gets more rights, maybe part of the Bundesrat, the federal representation, has to be elected rather than sent by local princes, maybe the Reichstag has to accept a new chancellor. That would in fact be the most probable thing, given increasing success of SPD and Zentrum during elections, Wilhelm might be forced to appoint a social democrat or at least a Zentrum-member as Reichskanzler when these parties control the Reichstag and thus legislation.
If he tried to rule against the constitution when such things happen, I think that thanks to inner tensions Germany would stay out of a war.