Actually it did have allusions. Don't you remember King Triton talking about the Keyblade: YouTube - Kingdom Hearts: Movies (part 12) (3:47- 4:32)
And Kairi's Grandomther's Speech?: YouTube - Kingdom Hearts: Traverse Town - Third Visit (1:24-2:43)
If those aren't allusions to BBS then I give up. (Not that they planned this but they might have had some clue as to what they would do if the series continued.)
No one said that it didn't have allusions to BBS, all we said was that it wasn't necessary for Sora to learn about TAV at that point in time. Possibly, in KH3, he will be ready to learn about them. If not, then oh well.