What I feel was most unfortunate in World War 1 was the ambiguity of the British in their promises to both the Jews for a homeland and to the Arabs for independence. It caused more harm than good. I feel the broken promises to both the Jews and Arabs were a major cause of the Near Eastern conflict we have today.
The Jews eventually gained a homeland in Israel after World War 2 when the British left. But, Great Britain and France left the Near East open for conflict after Israel was created in 1948.