Equipment was not a total loss for me. In fact, one of the above posts just awakened an old memory. One of the very first features I realized was missing, was in fact accessories and defense equipment. I was quickly like "Oh...it's missing" and then I completely forgot about it until I just read that post XD.
I do not miss Reaction Commands...at all. I am actually grateful to see that they have been removed, as they were utterly unecessary in Kingdom Hearts II. They were all flash and literally no substance. If I could actually be penalized for pressing the button too late/too early, I should be penalized. If I press the wrong button, I should be penalized. Birth By Sleep rectifies this issue with all of its context sensitive actions (well, most of them)
I would be lying if I said I missed the Gummi Ship. Did not miss it...or even think about it aside from the first time I left Land of Departure.
I did however, miss item synthesis. Not for conventional means, as I seldom ever used it. But obtaining Ultima Weapon through that was far less tedious than being forced to play mini-games from hell.