I'd like to take a moment to talk about Wound, a new battle mechanic from FFXIII-2. In my opinion, it's one of the single best additions to game mechanics the series has had in a long time. It's one of the first ways Square has added true difficulty to their games and their superbosses.
Take Yiazmat, for example. I don't consider Yiazmat a hard boss. He's cheap and can kill you easily, sure, but it's not a matter of difficulty, it's a matter of luck and patience. An unblockable instant-kill attack is not difficulty, nor is an incredibly high HP total.
What is difficulty is challenging mechanics, and Wound is great at that.
One of the major problem with making difficult bosses is the overabundance of healing in Final Fantasy games. White Magic is always prevalent, and you can frequently get truckloads of potions and elixirs throughout the games too. It's fairly easy for characters to stay topped off on health.
Oh, and the game also has set health caps. So, while dealing over the health cap with a standard attack (or executing multiple weaker attacks before a player can respond) is simply an unfair way to kill a player instantly, dealing less than that can be healed quickly and without trouble.
How, then, do you make a fight difficult without being unfair? And the answer: Wound damage.
By Wounding the player, you are manipulating their maximum HP. It's only a little bit at a time, but even a little can drastically change the way a battle plays out.
How many of us have switched to a healing Paradigm to top off throughout a battle? It happens in most boss fights, right? But how often do you cure Wound damage?
See, Wound damage can be cured (and this is very important), but only through the use of a Wound Potion. Wound Potions only heal 100 HP, but they also take away the Wound damage you've already accrued.
Now, let's look at boss battles then. Let's say you've got a boss whose standard attacks cause Wound damage equal to a quarter of the attack damage. The Wound damage starts to accrue, and you simply heal up your characters with White Magic and ignore the Wound damage. And then a superattack comes.
It can be anything. Let's take Ozma's meteor (another cheap, rather than difficult, boss) as an example. Instead of doing 9999 damage, it now does around 8000 reliably. No problem, you keep yourself healed up to full all the time because you know this guy's dangerous and... Oh, right, you've been Wounded, and your full healing isn't actually high enough to absorb that damage.
Suddenly, you have some strategizing to do. Wound Potions are a limited resource, and take valuable time away from your other plans. Furthermore, while they do cure your Wounds, they don't do much to actually cure your health. So if your healer takes a turn to cure Wounds, it won't matter that you have your max health back, if you don't also ensure that your current health gets topped off as well.
This has a huge affect on how you can plan for battles, and how your strategies will play out. That one extra variable doesn't seem like a lot, but it actually becomes crucially important to major bosses, and especially superbosses.
FFXIII-2 has some great boss fights, especially in the DLCs, and I'm pleased to say that I can't remember any of them that are as cheap as superbosses have been for the past few games. I think Wound damage is partially responsible for this, and I think it will do a lot to cut down on cheap superbosses in the future if they keep using it, and tweak it just a bit.