Yes, I know that but I'm also aware that he also wants the keyblade war which is what confuses me. A balanced world and a war are two different things. If MX where to gain that power, it is stated that he would use it to start another keyblade war when alreayd with that power he couldv'e just created a new balanced world.
Okay, let's clarify:
Master Xehanort dedicated his whole life researching the Keyblade War. After digging further into the matter, he found out about Kingdom Heart, a power so great that any human could turn into superhuman. After this, he began machinating a plan to create the world he envisioned; balance in light and dark. But Kingdom Hearts appeared before the past fighter because they started a war, so, what does Xehanort do? He plots and devises several plans to re-enact the Keyblade War so that Kingdom Hearts could be his! This is where Vanitas and Ventus come into play, and Terra. To summon KH he needed the X-blade, and to summon the X-Blade he needed two hearts pure; one of light and the other of darkness. With his fragile, old body, he wouldn't see his balanced world unfold, so, he changes his body into one younger; Terra.
That's all, in summation:
MX reenacted the KW to summon the Xblade and to summon KH to build the world he envisioned.