Update: The Great November Errata fixed one item in my blacklist, the Rod of Reaving. I'm glad, as it is probably the one that needed it the most. Now, if only they took a look at that helm...
Choosing magic items is the part I enjoy the least of building and leveling a character (or, as a DM, of planning encounters). There's just too many items, and I find most of them either too weak or uninteresting. This still leaves (after a bit of tedious filtering) a good amount of reasonable choices, but the presence of overpowered stuff renders all but a few of these obsolete. In order to improve the situation, I have started to compile a list of broken items, along with rule patches that bring them closer to my idea of balance.
The criteria I'm using to clasify items as overpowered are the following:
- Static modifiers, when present, should't affect the primary game statistics. Anything granting a flat, non-enhancenment bonus to defenses (and AC in particular), hit, or damage is suspect. Conditional modifiers can be fair game, as long as the conditions are difficult enough to meet - if something can reliably work almost every turn, it should be subject to the same rules as continuous bonuses.
- Strong daily powers are accepted, and even encouraged. In fact, it's hard to find examples of a daily power making an item too strong. The same can't be said about encounter or at-will powers - these tend to be easy to abuse.
Here's the list of offenders for the first Player's Handbook. I actually intended to include stuff from Player's Handbook 2, too, but I couldn't find anything that screamed broken to me. This is something remarkable, even considering the relatively few items in that book.
* Rod of reaving (Update: This item has been errataed. It's ability now only works on non-minions, which while not too elegant, is a perfectly serviceable solution)
This rod does horrible, horrible things to minions. Of course, in my experience, minions already have a hard time surviving past the first two round of any encounter, but this item's property allows you to kill one each turn, without any kind of attack roll, at the mere cost of a minor action. It could also be combined with various other Warlock feats and items, to curse several enemies in a given turn, annihilating armies of minions at once, though that is likely overkill.
Fix: Add this at the end of the item's Property: "this damage can't reduce an enemy to 0 hit points".
Comments: It was a pity that an interesting mechanic for damage dealing got overshadowed by it's application for minion slaughter. With the minion interaction gone, we are left with a magic item capable of dealing a remarkable amount of extra damage over the course of an encounter, but spread in such a way that it is not too troublesome.
The boots aren't so much broken as too good for their level. They feature an effect (ignoring the worst part of being knocked prone, which is losing a move action) that I would find competitive for a paragon, or maybe even an epic magic item for the same slot. I usually don't bother with correcting a magic item's level, but these boots are tied for the lowest level for magical footwear in the game, which is a bit too much for me.
Fix: Change power from at-will to Encounter. Add a Level 12 version with "this power becomes an at-will power".
If your character is melee oriented and capable of charging (having Str as a primary ability, or Melee Training), this item is too good to pass. The damage bonus is huge, and it's not that difficult to make a charge every other turn, so it can come up quite often. Worn by a character without a specific dedication to charge attacks, this will more often than not make charges more effective than at-will powers, changing the default strategy to 'charge whenever possible', and resulting in a slight damage increase overall. However, it really shines with specialized chargers, such as Barbarians or some Druid builds - to the point of brokenness.
Fix: Remove property, add the following power.
Power (Encounter): Free action. Use this power when you hit with a charge attack. The attack deals an extra 1d6 damage.
Level 16: 2d6 extra damage.
Level 26: 3d6 extra damage.