I got a quick question for you all. There is always talk about the one 'missing key' that everybody seems to miss... Is this actually the same key at all that we are all referring too? I do not remember the temple vividly so I'll try to explain as best as I can.
I remember one part where I was on the third floor of a room and there was a hole in the center of the room that led to the second and first floor. On the third floor you can play the song on the Ocarina to lower the water to the first floor. I'd do that, but as the water was lowering, I'd hug against one of the walls and catch onto a ledge, so that I'm actually on the second floor. From there I either opened a treasure chest... or bombed a wall that led to a treasure chest with the small key. (I don't remember exactly). I never really did find out if there was another way of getting this small key, but that is what I always did.
The other key that I can think of, is the one at the bottom of the central room. There was the tower like thing in the middle of the large circular room within the temple. At the very bottom of this tower, there was a small block. I think the first time you go into this tower, the water level is at the bottom, so the block covers a hole. However, the second time you enter this area, the water level has raised. You then need to use the iron boots to sink through that hole, which leads to another small key I believe.
Am I right with these two small keys? If I recall, these were the two 'tough' ones, but perhaps I'm just talking jibberesh and don't recall them. Either way, I thought they were hard (and I forgot if you got the Dungeon Map and Compass already at this point). If you did already get them, I have no problem with hard to reach treasure chests since the map/compass should guide you in that direction. If you didn't get the map/compass, perhaps they should have just allowed Link to find those before hand.