I, for one, think this was an interesting idea, instead. It is a conflictual idea. When Ares trained Diana, he wanted her to fully take his place, to take over those aspects of war he represented.
Just by staying with him, though, Diana began to change him. He started to care for her:
When he asked her to kill the Minotaur and she refused, he realized how Diana wouldn't have ever become like him, that she had chosen a path different from his, that a path different from his really existed, and that without knowing it he had already made that choice once, when, after Diana yielded, he had decided not to kill her.
In that moment for the first time he had ended a 'war' without the death of his enemy. And he left because he was hurted by that, because he didn't think another way existed before that moment, because he didn't think that war could be different. He was resigned in his role, and even if he was tired of it he didn't know there was another choice, even if he too aspired to rest, to peace, like we see when he dreams of one day passing his role to Diana:
http://static.comicvine.com/uploads/...n-zone-008.jpg
and also from Hera's words at the end, when she wishes him to find in death what he couldn't obtain in life: peace.
He thought that the meaning of war was to end conflict and that to do that he had to kill the enemy not to give him the chance to return and try to kill him. Diana instead decided not to kill the Minotaur and in doing so she had gained his respect and even after ten years he still remembers her and probably will become her ally.
Actually, thinking about the differences between Perez's and Azzarello's Ares I have recently come to this conclusion: I think that while Perez's Ares stopped his plan about the nuclear war when he realized that it would have lead only to the death of everything, war included, Azzarello's Ares, before meeting Diana and thinking she could take his role, would have continued with that plan because to end war was what he really wanted to do, and he seemed to see death as the only solution.
In the years between that 0 issue and when we saw him again Ares had changed a lot, but he looked sick, because he was trying but he couldn't really change completely. We saw him still in war zones, covered in blood. When he died and left his role to her he did so not thinking she would become like him, but that she would do better, much better than him. He knew she could change the meaning of war. He wanted her to. But he knew it wouldn't have been easy, he knew it would have been a burden.
So Diana became god of war in Ares's place, but she never became like he was, and she didn’t start to impersonate Athena's role either. She didn't become 'Order, strategy, wisdom, discipline'. She became a god of war who wanted to change war and even put an end to war. It doesn't seem to me Athena's role, nor Ares, it's a role of her own.
A role she doesn't like but she must shoulder, and that of course creates conflicts inside her. Goddess of Peace or of Truth wouldn't have created any conflicts like god of war does, so they wouldn't have been as interesting to me. For one, these two issues wouldn't have existed if she wasn't god of war but she was goddess of peace from the beginning.
I would like her to manage to change the meaning of war from within instead of what we have seen here...and there's still hope we will because these are future ends issues that probably won't happen. This offers so many opportunities for interesting storylines and to explore Diana's personality and to see how she always struggles to be better. I liked the WW FE issue because of that. Because we saw what she struggles with.
Azzarello has made her god of war, but has never made her symbolize 'Chaos, bloodlust, savagery'. We can almost say she is struggling to end those aspects of war. We could see it just the moment after she became god of war, when she spared the First Born. Would the god of 'slaughter' do it? Or would the god of war be interested in changing the amazons instead of making them continue with their habits? Would he struggle to obtain peace between the amazons and sons? I don't think so. Azzarello has never depicted her in that way.
If something she seems more the god of war in the classical sense in Justice League, and that started wayyyy before Azzarello made her really god of war, since it happened in WW 23, while already in Justice League 9, 10, ecc... she was already depicted like that.
What Azzarello has done is shifting the fight Diana has always had against war from outside against Ares to inside herself. She is still fighting war, only now she has to do that from within. That for me was a really interesting thing to do. More so because Diana even while struggling for peace has always been a warrior too. Now she has an internal battle to fight.
It wouldn't have worked with Athena. She was never her enemy, and she doesn't represent the worst aspect of war like Ares did.
Moreover, by internalizing the fight against War Azzarello has even made it more realistic for me. To end war is not as easy as defeating an external enemy, because you can be sure that another one will raise. It is a change that the society as a whole has to make from within. War will end when everyone will understand that it is something that has to end, when everyone will see the other not as an enemy but as an ally and a friend, when everyone will stop to use it for his/her ends. That is a much more difficult thing to achieve than defeating an enemy.
You can't give him all the faults for the fact war exists. War doesn't exist because there's an enemy, but because you see him as an enemy, and probably he has become your enemy for the same reason, because he has seen you as his enemy. You want to end a war? You have to be the first to put down your weapons or else no one will. You have to trust your enemy to do the same. A great risk.
In this sense does this remind someone? xD Someone that gives her trust even to Strife? xD
I find interesting how turning enemies into allies has always been Wonder Woman's way, and she has done it a lot in Azzarello's run too. She has the right means to end war. I think this role is just perfect for her, but of course it is not an easy one. And it is not really new. It has always been her role, hasn't it? Her mission has always been to give the example in this sense. And you can give a better example for something if you are involved too into it instead of it being an external thing, because you can understand it better.
Becoming the goddess of Peace would be the culmination of everything, a state she can manage to reach only when she will have finally succeeded into doing these changes...not something she can do just yet. Anyway, I want to think that in SMWW FE she managed to do that only because she realized it. Because she realized that continuing to see Nemesis as her enemy, the war wouldn't ever have ended.