The problem with that is there's absolutely no way to be sure that Germany would keep its word after settling France and Russia. The primary reason Britain sided with France is not that Germany was the aggressor or violated Belgian neutrality, but that Germany was a naval threat that France wasn't. See, Germany had about twice France's population and three times its industry. There was no way that France could build an army that could oppose Germany and a navy that could oppose Britain. But Germany could build an army that could oppose France AND Russia AND a navy that could oppose Britain. In 1914, its navy was still smaller than Britain's but only because Britain had deliberately committed to keeping its navy bigger. The entente between France and Britain was that France should keep a navy only big enough to maintain its colonies, while focusing on its army to oppose germany, while Britain would focus on its navy and in the event of war with Germany, take over responsibility for shielding Atlantic France from Germany's navy. If Britain had given Germany a free hand in Europe, then there would be nothing to stop them from reneging on any promises they made, and continuing to build their navy, now undistracted by any other continental threats.
The constant policy of Britain over the years was to ally against the most powerful continental country. Throughout history, this was usually France, but at other times they switched to supporting France against Spain, against Austria, against Russia and against Germany, whenever these other countries threatened to dominate the continent. Britain's strategy, for a millenium, has been to keep any one nation from dominating Europe, and I don't think this sort of hindsight really alters that fundamental strategic truth. If Britain had let Germany have its way, it would have been left alone at Germany's mercy, and dependent on Germany's honor.
Absolutely. But with hindsight, relying on the Kaiser to keep his word was a better bet than relying on Hitler to keep his.
One interesting question is 'what happens if Germany does come to dominate Europe?'; and there seem to be two answers available to us from the last century of history, that were not available to the denizens of 1914.
The first example of German dominance is the events of the early 1940s; With a murderous dictator in charge, the result was horrific and required a long and costly war, ending with the partition of Germany, to correct.
The second example is the period form the early 1990s until today; With a European political union dominated by, but not under the complete control of, Germany. The result of this is not yet clear; The Germans (and to a lesser extent, the French) have been pushing for a 'United States of Europe', but by attempting to introduce this slowly (due to opposition from other EU member nations, particularly Britain, and due to opposition from popular opinion amongst the ordinary citizens) has led to a number of major problems - running a single currency with a couple of dozen separate fiscal policies has caused a disaster for the Southern states, while unfairly enriching the industrialised states to the North, for example.
Now the Union seems likely to break up - or at least to shed a few members. But the core continental power will still be Germany; and for the average European Union citizen, this doesn't seem to be a particularly bad outcome. As Tom Lehrer memorably sang:
Once all the Germans were warlike, and mean
But that couldn't happen again.
We taught them a lesson, in 1918,
And they've hardly bothered us since then.
My feeling is that there is a 'natural' maximum size for a nation state that is determined by communications; The Roman Empire could grow large, because of good roads; The countries in the Americas could grow large because of railroads and the telegraph - and because the smaller states from which they were assembled hadn't had the time to build too much history of war and rivalry. But European nations started out small, with geographic barriers forming the borders; and now they are really a bit too small for modern, high-tech nation states; but are shackled by nationalism and linguistic barriers, preventing them from uniting effectively. A 'United States of Europe' is, I believe, inevitable; but whether it includes such outliers as Greece or Britain; and what the effects of being in or out might be for those 'edge' states, remains to be seen.
Certainly in the first half of the 20th century, a Europe dominated by Germany was very much against British interests, and likely against the interests of most (non-German) European citizens. But it is far less obvious today that a German dominated Europe is a bad thing; particularly if Britain remains in a position to oppose German interests in the EU Parliament. A British exit from the EU would leave Germany very much dominant from the Atlantic to the Russian border; and the only way for Britain to remain a power in such circumstances would be for her to rely on her overseas empire. But the British Empire no longer exists.
In 1914, Britain had an Empire to keep her rich enough to be the world's foremost naval power; and she had her diplomatic finger on the scale of power balance in a divided Europe. Those two things made her a Great Power. She now has neither, and risks becoming almost completely irrelevant on the world stage. The First World War was not enough to break her; but it laid the foundations for the Second, and that drained her power to the point where she could no longer dominate her imperial possessions; and shorn of an empire, she had no choice but to become a part of an increasingly united European trading bloc, which ultimately led to a unified French and German policy for a united Europe, destroying the conflict upon which British diplomacy has relied for so long.
