Many of the Earlier wars (post mediveal) were centered around the struggle between the Habsurgs and (royal) France (latter winning sort of

) and their various allies (including the Ottomans sometimes) - OR the HAbsburgs/Russias vs Ottomans or HAbsburgs (Spanish) vs Brits
onsidering the overall result of those wars their biggest changes were centered in Europe. - with only minor changes around the world.
in This regards I consider the 7 years war the main contender for the "first" real "world war". It shattered the First French colonial Empire and left a dominating British "Empire".
The ARW - had the main actions within the 13 colonies - with a bit action elsewhere - While it was important in being the first real defeat of the British (since the 100 years war) it was not really worldcovering.
The same with the French Revolutinary/Napoleonic wars (part of a greater war, but essentially the same). While some action is fought worldwide - the greater world is not really affected by the outcome - Europe was shaped anew, but the rest of the world stayed mostly the same.
NO world wars in the 19th century
WWI - no doubt about this - both sides had a world spanning campaign - someplaces quite short, but only due to overwhelming superiority of the Entente powers - and both Europe and the World were changed (German colonial empire destroyed, ...)
Well the Second World War - IMHO had a much more limited scope than TGW - basically it was two wars fought at the same time where one side had a strong cooperation and their enemies were allied mostly "on paper". Casualties were high true, but that alone does not qualify (Mongol conquests, Chinese wars,...)
Well if you consider that afterwards only two instead of three dominating political systems remained - the you get it properly named
War on terror, sorry that implicates that terrorists are soldiers - thats no war thats a police action (war would give the terrorists too much "honor")