Hell no it's not worth it. While ultimately the price of the extra goodies is subjective, it can still fairly be compared to the stuff other editions get. So with that, let's see just how much of a ripoff this set is:
KH 2.5:
-Both games, for a total value of $60
-A 9 inch plush, a box, a steel book and a 30-page hardcover book for a total value of $40
-Hence, we get the $100 price tag
Now for some similar stuff with the same (or cheaper) price tag (MSRP of course):
Your average Blizzard Entertainment Collector's Edition:
-The game/expansion itself, anywhere from $40 to $60. Let's just settle down for an even $50.
-The box to hold everything in, a soundtrack CD, a making-of DVD and blu-ray, a hefty 200-plus page hardcover art book, and usually some other bonus goodie(s), ranging from a mouse pad, to deck of cards, to comic book, to speciality USB with games pre-loaded on it - for a total value of $40.
-Your typical Blizzard collector's edition usually costs $80, but never goes above $100.
Zone of the Enders HD Collection Limited Edition:
-The game itself, for a total of $40
-Soundtrack CD, 100-page art book, and box for $20
-Total is $60
BlazBlue Chronophantasma Limited Box:
-The game itself, for a total of $50
-Box to hold it all, a nendoroid figurine, soundtrack CD, 30-page art book, bonus blu-ray, double-sided poster/move chart, for $30.
-Total is $80
And that's just the limited edition crap in my current field of vision. To put it bluntly, the Kingdom Hearts HD 2.5 ReMIX Collector's Edition is asking you to shell out a whole lot for a whole lot of nothing. The plush and steel book are awesome, and the addition of 1.5 is a nice gesture, but no way in hell does it all together stack $60 on top of the price. The pin is something you already get with every first print copy, and that "art book" is a bad joke. ESPECIALLY if you already have 1.5.