Well I think it is not fair to instatly get to 100%. What about other countriers slowly preparing for a war? with 100% WT instant, they would have no chance to do anything.
Basically what you are saying is that if somebody want to wage a war (not for ethiopia I guess), they will instantly make a world conflict. Remember, that Democratic countries tried not to get into war as long as possible. If Hitler didn´t attack Poland, Allies would let him and his country to occupy Austria and Czechoslovakia for free without any sanctions or whatsoever. I don´t think that Allies would instantly declare war on Japan just because they did something to China, since China is very far and also China wasn´t ally to any of these countries (USA GB FRANCE etc). Also, in China there was a coup in that time (for People.Rep.) so I doubt other nations would be in such a hurry with declaring war.
I think that it will be better to wait for 1. Balancing(cause things can change A LOT) 2. Dev Diary 3. Seeing it in another playthrough