There are several things wrong with the arguments in favor of the upgrade
1 - "There are as many worlds as stars in the sky"... except that it's literal, since every star in the sky is another world, stated and shown more than once. But KH's calc uses the amount of worlds seen being restored, which is the safe lowball.
2 - The stars seen in Stitch's world... are just other worlds. He uses the Hyperdrive, but nothing says he went to Earth iirc. We even find him years later in Radiant Garden
3 - Pooh's world and the Symphony of sorcery's dimensions are literally a book and some songs, and
this is what most likely happens
4 - Marluxia isn't the 3rd strongest member, that same WoG referenced before actually said that the 3rd are Xaldin and Lexaeus, tied for the spot
5 - The feat in Aqua's battle against Terranort is most likely her interacting with Terra's heart, as we see the real him and the guardian trying to stop Aqua from reaching him
6 - About Marluxia's dimensions, not sure if it's legit as it might be related to Castle Oblivion shenanigans, but if it is it might be an outlier.
7 - Now, I don't remember if the calc for KH considered the worlds as solar systems or not, but if it didn't, unless it wouldn't reach higher than Zeus' feat, it might be worth a look into it. Also KH didn't restore space, only the worlds.
7 - KH3 will come out in less than 2 months, and I'm planning on doing a general revision of the verse after that
@TP they're called Realm of Light and Realm of Darkness (which basically are existence and non-existence, but I'll get to this another time)