0.2's last boss is the worst (non optional) designed boss in the entire series, by far. Everything about that fight reeks of bad design, and figuring out how to even survive, let alone damage the final phase is obtuse as all hell. Every single one of Aqua's defensive and mobility options are nigh useless in that last fight.
It's like the entire fight was designed with Birth by Sleep's mechanics and options (infinte cartwheel spam, access to more than one cast of Cure at a time without a full recharge, etc.) in mind and they just didn't bother balancing it.
I wouldn't be too surprised if that was boss in KH3 and they just ported it straight to 0.2...