Is the DLC even worth it (overpowered spells aside)?
The DLC boss fights are probably the highlight of the add-on content. Any given person's "Top 5 Bosses in Dark Souls" is likely to have two or more plucked from the extra content. None of them are gimmick fights (like Ceaseless Discharge or Bed of Chaos) and they're all tougher than the average boss in the original game content. Plus, one of them is a decent
The areas themselves don't shine so lustrously, though.
The Royal Wood and the Abyss seem like a bit of rush jobs, even though the flavor behind the former somewhat justifies the rehashing of content. I don't want to "spoil" the realization too much though...FROM was pretty clever here. Even the enemies play into the theme. The foes in this area are new, but familiar...if that makes any sense.
Chasm of the Abyss, on the other hand, comes off as a cheap Tomb of the Giants knockoff; another dark cave, except this one lacks enemy variety, is far smaller in scope, and simply isn't as lovingly designed as the area from which CotA draws heavily from. There is a nifty easter-egg/secret built in to the level (and how it can connect back to the main game is impressive), but not much else really elevates it. Well, besides the fact that it can be mercifully brief (the boss here is a wee bit tricky) and, hey, humanity farming was never so easy.
Oolacile Township is the most sizeable area and offers a bunch of hidden paths and niches to the diligent explorer. Unfortunately, it too is hobbled by the lack of enemy variety; there's two kinds of baddies and a mini-boss who only appears once (unless you are Gravelord'd). The concept of descending from the rooftops of a fallen city to the lower reaches is interesting; kind of like a twist on the Undead Burg. But a simple melee foe and a corrupted sorcerer, while lethal enough, don't provide the variety that the better areas in the main game delivered.
Items are pretty decent in the DLC, though some of the spell additions are stupidly good. There are some cool-looking armor sets (including a light armor set with a modicum of poise), a couple new special souls to craft weapons, and some nifty weapons (such as the dagger set with unique off-hand movesets/traits). I was personally let down by the lack of any new Miracles or anything really aimed at Faith builds as just about every other build received some treats.
All in all, it's certainly worth playing, but 15 KWABUX may be a bit steep unless you feel like donating* your judengeld to FROM and/or sending a message to their publishers that these types of games can make a tidy profit.
*I assume the margins on DLC are a lot higher than the base game.