Has something surprised you in retrospect? Areas that you didn't like before that you do now, or things that ages more poorly than you thought?
Hmm, maybe none of that this time per se, but when I replayed these on PS3 I think I may have felt some of that, so let me try to tune in to past me for a minute lol.
One thing that surprised me was how short the first game actually is. I felt like I was blasting through it and the story moved pretty quick. I don't know if it's because I was worse at games as a kid so it took me longer to get through, or because as a kid it was all new and fresh so I explored absolutely every corner which prolonged my experience (plus just naturally not knowing where to go or what to do on a first playthrough), and then also my imagination as a kid. I imagined these conversation between Sora, Donald, and Goofy along the journey, just like, normal chatter that would naturally happen when traveling. Or I'd go and randomly visit Squall, Aerith, and gang and see if they said anything new then had pretend conversation with them... Childhood me fleshed out the character relationships way more than they actually were lol.
As far as world likes and dislikes, as a kid I had a hard time with a couple worlds. I struggled with Deep Jungle as a kid, getting turned around and struggling to get past the Clayton Stealth Sneak fight (didn't help that I didn't have a memory card for the first few weeks. So I always had to restart each day then get stuck here). I got turned around in Monstro a good bit, and also Atlantica.
Something I wish was different if changed that's a minor thing I think is that I wish you could interact with stuff, even during battle. Several times I've gotten a little peeved finally about to grab the dolphin or wanting to open a chest I happened upon and couldn't until I cleared the room. Just a minor thing, but y'know.
A huge plus to the Final Mix edition is frickin' Leaf Bracer. I didn't start this playthrough with the shield like a fool and regret it because not having Leaf Bracer or Second Chance on Proud has had me get beaten down a couple times when I was careless, especially since I haven't level grinded at all yet lol.
I also think I just have a memory of the worlds being way bigger than they are, but again, I think that's attributed to how big they felt as a kid and also the fact that they don't feel nearly as linear to me as the worlds in ever game after, and I kind of prefer that more non-linearity.