I just completed Big Hero 6 and Pirates of the Caribbean for my replay. On finding a good minimum level: I stopped at Level 15 after grinding a bit in Frozen and it's felt like a good balance so far, though I'm not sure if it's actually a better experience or if it's BH6 and PotC being much easier worlds to complete
While I enjoyed BH6 on my first playthrough, I've honestly started to dislike it and Pirates. I don't mind the regular gauntlets / encounters, it's more the bosses being either really easy or really gimmicky. The gimmicky bosses were nice diversions the first time, but now that I'm replaying the game solely to mess around with the combat, they're just getting in the way of the actual fun parts.
I also just noticed that there's quite a few options, like toggling the cinematics for Attractions / Links, removing the cinematic camera angles for combo enders and there's even an option for shortened formchange animations. That option changes all the unique formchange animations into a generic activation animation that looks a lot like the Drive activation animation from KH2. If you're into that kind of thing, or dislike the really long activations, then it's good to switch it to that.
Personally, I've toggled it back to the default setting (i.e. showing the transformation animations). The longer animations are annoying, but some keyblades do get more utility with the default animations (e.g. Shooting Star will push you forward during its animation, so it's not bad as a quick escape option in some situations; Happy Gear's transformations can add meaty, extra damage to your combos, Wheel of Fate and Nano Gear have really good stagger / interrupt-ability on their animations etc.). It really depends on what you're utilizing.
