Recently, I've listened to Dan Carlin's fine (if a bit overlong) podcast series on the Great War, Blueprint for Armageddon (in six parts, and currently free on his site, Hardcore History. Well worth your time), and read the book Carlin acknowledges as a significant source, Peter Hart's The Great War, a Combat History of the First World War, which I also recommend, with this caveat: the maps are terrible. You'll need something like the resource I used, Arthur Banks's A Military Atlas of the First World War to have some idea of what is going on.
Together, those sources gave me much better appreciation for the military challenges of winning the war on the Western Front, particularly from the Allied side. In essence: you couldn't. The French and British got better and better at attacking as the war progressed, learning how to use moving barrages, how to concentrate their forces, how do combined operations with aircraft and tanks. All that ever got them was a few miles and a lot of dead men. Even at their best and most organized, each offensive would reach its initial objectives and then, while they regrouped for the next round, the Germans would also reorganize and present another defensive line. Not a single one of these offensives achieved any larger objective.
And many of them were not at all well-organized. Over and over, Hart tells how either the British or French would be hard-pressed, about to collapse, and desperately request their allies to launch an offensive to take some of the pressure off. Even though even well-planned and well-resourced offensives failed, the commanders would scramble to comply, essentially slaughtering thousands of men to maintain a feeling of alliance. Nothing ever succeeded.
So that is why the whole four years feels like one endless static nightmare, except in the beginning, at the Battle of the Frontiers, and at the end, when moving armies meant that the casualties were way higher that they were even in brutal assaults on trenches. Carlin refuses to detail much of 1915, because every horrible battle was exactly like every other horrible battle, and no one yet had much of a clue how to manage things.
So no wonder that people with a sense of narrative, like Churchill and Lloyd-George, became what were called Easterners, trying to find some way they could attack without facing the iron wall of the German army in the West. The results were just as terrible: Gallipoli and Salonika (where, after getting all bent out of shape about Germany's violation of Belgian neutrality, the British blithely violated Greek neutrality in pursuit of their own goals). Even the successful Middle East campaigns, featuring the charismatic Lawrence of Arabia, were just sideshows that drew resources from the main fight. Not one of those operations were worth the effort.
You could tell bad commanders by the fact that they killed way more of their own troops, but there was no way to be a truly good commander. No genius could come up with some spectacular tactic. New weapons systems, like tanks, would work well at first and then break down. No propaganda could affect the enemy's will to resist.
None of us would ever come up with something like this as the basis of an SF or fantasy novel. There we like people who affect things, make things happen, and can anticipate the actions of the enemy. None of that on the Western Front. The best thing would have been for everyone involved to negotiate some kind of status quo ante treaty after the First Battle of Ypres in November 1914. After all, by the end of 1914, the French alone had already lost something like 300,000 dead, an unbelievable 27,000 on just one day, August 22.
Of course, everyone still believed there was a story to tell, one with some kind of narrative. It's startling to think how long they would have to wait for the end of the story.