I think he's implied to want to remake the world in BBS but he says in the BBS reports that there is actually too much light in the world and there needs to be more darkness to restore the balance in the world. But at the end of KH3 he thinks that darkness has swallowed the light, leaving nothing but ruin, and that there needs to be less darkness, not more.
Not quite but you need his scene in Re:Mind, his reports, and his talk in KH3 to get the full picture.
The gist is he doesn't think balance can't be restored to the world as it is period. Darkness did swallow the light and leave the world ruined, that's a fact of their world's history not his opinion. However in time the world reorganized, darkness was largely snuffed out, and a new order of light was built. The problem is that when he saw this "light" first hand he wasn't impressed, he saw the current light as false light. In his eyes the hearts of people aren't bright they are dark and the light they have that suppresses that darkness is something that WILL break and cave, and when it does the darkness they held back will overrun and destroy them. If it was just some people being inevitably consumed by their own darkness it be one thing, but Xehanort worries that this permeates the entirety of their world. That when the light finally breaks the darkness will consume their world throwing it into chaos.
Xehanort was raised from a young boy to believe his destiny, his purpose, his reason for existing as a keyblade wielder is to protect the world and the people in it in a way not much different from say Sora. Albeit Sora came to that conclusion himself while Xehanort had it drilled into him by his training. The issue comes that he starts to believe this task is impossible, that you can't save the current people or this world, it's just fighting to prolong an inevitable end. Maybe he's right, maybe he's wrong, whatever the case is that Xehanort couldn't accept this.
He wandered the world seeking an answer to how to fix things and then he eventually found it in the keyblade war. He believes that if he creates the X-blade re-enacting the keyblade war he would be granted the power to remake the world. Thus Xehanort's path was set, he would return the world to is primordial state of a void of darkness where only the true light of kingdom hearts exists and to do that he would need to crush the false light that exists in order to create the darkness he needed to achieve the power of kingdom hearts. Once he made his new world In time history would repeat itself, people would be born from that light and they would have hearts, and he would be there to ensure when darkness inevitably blossoms in their hearts that this time he would guide them to ensure their darkness doesn't grow out of control and upset the balance destroying the world again.
The problem is beyond the fact that he wanted basically just scrap every living thing disregarding their right to life or the worlds and lives they've built...is that Xehanort planned to control everything. He wasn't going to allow people to live their lives and follow their hearts, he was going to dictate their lives as an all powerful god to ensure the people born create the world HE wants. Which ties back to his belief that the strong have the right to rule and the weak should just yield and be ruled. That is why Sora told Xehanort that he isn't the leader the world needs, because a real leader wouldn't try to control a person's destiny. A leader would let a person do what their heart needs to do, and would be there to support and guide them down whatever path they choose to take being there for them when things get rough. You know the kind of thing Sora does, he doesn't control people he lets them do what they need to and tries to support and help them if they go astray like he did with Riku.
In essence Xehanort is exactly like a Foreteller, you could think of him as being almost like a 7th one. A keyblade wielder with knowledge of the future, who believes if he starts a war he can change the world and guide it. Who is trapped in a cyclical feeling of helplessness and hopeless that the world and people are doomed and he can't do anything but sit by and watch it...which then drives him to act and do things he knows he shouldn't. He even understands he's not the one meant to lead the world but no one else is standing up so dang it he has the power he is at least going to try, even if that means he has to take on the role of a villain and dictator.
Which is why Sora manages to eventually change him, because Sora is anthical to all his beliefs. No matter how many times he tried to break Sora's "false light", no matter how many times he tried to drag him into darkness, no matter how much he tried to predict Sora's actions...he always failed. Sometimes Sora's heart was weak and gave in but his light never truly went out, it always bounced back. Even when he became a heartless his light held on, even when he DIED his heart managed to linger. Granted it did all that because of his friends but that's exactly Xehanort's issue. Sora induces his weird qualities of bright and hopefulness in other people, Sora's presence in the hearts of others makes other people start to challenge what Xehanort's believes to be true, which is to say Sora who is sort of the baseline of a "normal" person in their world is just helping others do what they always could do even if they lost sight of that.
Sora and his friends working together show that Xehanort is wrong. But for the longest time he can't understand that, he can't understand hearts and never has been able to which is why he takes such a cold rigid scientific response to them, the true power and nature of the heart is lost on him. That's why what DiZ said is true, any world any empire Xehanort creates would be empire of ignorance. He couldn't understand hearts and that's why he could never be the leader the world needs, so he was going to create a world where he didn't need to understand to lead...where he could just control everyone though his sheer power over the world. Just like his organization where instead of make a group of different people he unifies as comrades...he saw them as a bunch of meat puppets he just had to manipulate long enough to turn them into himself then he have an organization made by him, ruled by him, and composed of just him.
It's only at the very end after everything and after reconciling with Eraqus that he FINALLY gets it, that it's not too late for the people or for this world. Sora's group have thoroughly checkmated Xehanort and he finally accepts his loss, handing over the X-blade both to stop his plan and also symbolically it's him regaining hope for the world and its people.