Honestly, I feel like they covered all the bases here aside from some sort of soundtrack. You have a steelbook and an artbook, which are classic CE inclusions. The pin was an obvious and welcome choice, to match all the previous KH special editions. And then you have high quality figures of Sora, Donald, and Goofy. The soundtrack thing, I don't get why they excluded that. This series is known for its music, they could have at least included a "Selections" disc or something. Another thing to note is that the inclusion of DLC content typically makes the marketing image for a special edition looks bigger and better, and since KH3 has none planned at the moment and Nomura doesn't like Season Passes (bless) we're getting none of that here, and DLC is a big staple in modern special editions.
I know a lot of people wanted a life-size Keyblade replica for the collector's edition, but that would have been a bit unfeasible and very expensive. Given that the Proplica Keyblade just released and that thing is basically a perfect Keyblade replica, I can tell you that the thing is WAY too big to be included as a collector's edition piece. Not to mention that would have made the price very expensive and it would have been very hard to produce enough of those to meet demand. The incredibly limited supply of the FFXV Ultimate Edition was absurd, so I imagine they didn't want to repeat that here and make something that was difficult to produce large quantities of.
Honestly, aside from the soundtrack thing, I'm not sure why some people are so angry over this. I agree that it does feel a bit lacking in comparison to some of Square's other collector's editions, but I feel like they included everything that made sense for this series. Square already has quite a bit of KH merchandise on their store and they almost never recycle things for their special editions, so things like Keyblade keychains, necklaces, acrylic stands, and so forth, they likely didn't want to include anything that people might already have purchased previously (that was a complaint with the 2.5 special edition when they included the previously released Shadow plushie).