I don't think it's a water temple. There was water in it, yes, but not enough to warrant the label in my opinion.
Yeah... It included water more thematically than it did in terms of gameplay; there was very little water to the gameplay of the dungeon. This isn't a case where you can strictly define it as being about water.
Anyway, the Ancient Cistern was a mixed bag for me. Conceptually, it was the best dungeon of the game. I loved the mix of totally different ideas in the dungeon to turn it into a totally unique concept, one not based or reliant entirely on each of its individual elements. And the creepy portions mark my favorite spooky area in any Zelda game. I also like how it's likely based on
The Spider's Thread, as Matt pointed out to me on Skype. I don't know if they
actually based it on the story or not, but the similarities are extremely striking, especially since the Cistern's underground does resemble a pretty standard Eastern concept of the underworld.
However, I thought that, aside from its boss and miniboss, the Ancient Cistern was the worst-designed dungeon of the game. Plenty of the puzzles were decent, but the ones with the whip, if they can even be called puzzles, were underwhelming. They did very little with the whip that was unique, and instead it acted as a basic item that was only useful because certain switches could only be interacted with using it. There were only a few creative uses of it in the dungeon, and after the dungeon it was almost useless. Worst item of the game, IMO, and the dungeon is hurt because of it.
The underground portion was also extremely underwhelming I thought. The Cursed Bokoblins were really no differently than a standard Bokoblin, visually. I guess they take a long time to die if you don't do the Ending Blow, but ultimately I still was able to fight them like any other enemy. They should have been endless or at least far more numerous and harder to kill. The underground portion also felt like an afterthought, because it was incredibly brief and seemed almost pointless in the grand scheme of the dungeon. Really, that brief portion where you're in the sewer overlooking the underground was more impressive in terms of presentation than actually being in that underground area. This area needed to be done better, and especially they needed to make it longer.
I'm gonna give the dungeon another chance on my Hero Mode playthrough, but I doubt my mind is going to change in regards to it being the worst designed dungeon of the game.