Well many of the things you have said aren't actually claimed by Xehanort. I don't recall him saying he knew that the X Blade would fail, and it's probably pretty obvious that Terra would resist him. He never claims to know any of those things. What he knew is that his original Organization XIII would, for the most part, fail. So like any good villain, he made fail-safes to ensure he could plant his heart into his new Organization XIII. Even now there are still many unknowns about what even happened to Terra and his heart. But because Xehanort's new goal after BBS was to make thirteen darknesses to clash with seven lights, he attempted to take Terra to add to his ranks.
Honestly, when you piece it together correctly, it really does make sense. IMO it is a fresh and rather unexpected twist. You can't just look at it as "it's time travel so it must be garbage." You have to look at all the variables.
Exactly, Xehanort on the contrary even admitted that he made errors in hs haste, the difference is only that he is crazy prepared and his errors actually don't do him any harm in the long run.
His ultimate goals got derailed three times, once by the BBS crew and twice by the efforts of Sora and his friends, yet Xehanort made just sure he will be able to try a fourth time by preparing some counter measures.
On top of this, he now also accounts for the errors he made those times and pays attention not to repeat them.
Not looking at all the variables in play seems to be exactly the problem of the OP, as when you piece everything together it really does make sense, heck, Nomura was alluding to the "true goal" of the Organisation even way back when the Director's Report to KH2 was released.
Connecting the dots is always a necessity in the KH series and even if we can't make full sense out of it right now that's only because the puzzle still isnt complete as Nomura left several pieces out to solve later.
There is also nothing "destroyed" about the story in my book since many things I already suspected from earlier reports and interviews are turning out to be true.
I wouldn't say that it was disappointing, but just horribly convenient yet inevitable. MX was planning for years to re-create the Keyblade War, he was sure to have some back up plans along the way. He said it himself: destiny is never left to chance.
Xehanort is a schemer, Yen Sid acknowledged that in Re: Coded and he already said to Terra in Blank Points that he has "many roads" left open so having his plans laid out in several steps ahead isn't that surprising.
Although I disagree with that destiny/fate (what's the difference between those anyways?) is predetermined babbling as people have proven again and again that fate
can be changed with enough effort.
That "fate"-speech of MX about the BBS-crew towards Mickey was just MX playing his way out of Mickey's accusations that it was he and his stupid plans that screwed over Terra, Aqua and Ventus. Xehanort isn't a god (although he wants to be one) who decides what is fated and what not, since it are solely his schemes which screw over so many hearts and people and not some ominous "destiny" or fate.
Or, to make it short. Xehanort just shows Mickey how many fucks he gives about the horrible things that befell TAV: None at all.
He's completely out of empathy and remorse for
anything.
