The fact that the developers said that there would be less dungeons/temples, but the game would be more dense, makes we want to think there would be more than one less dungeon/temple than TP. Twilight Princess has Forest, Fire, Water, Desert, Snow/Ice, Temple of Time, City in the Sky, Palace of Twilight and Hyrule Castle. That's like 9 dungeon/temples altogether. Though, Snowpeak Ruins isn't really so much a temple, just considered one. City of the Sky could be considering the same. They still count, for what this is worth though.
So, we have 9 dungeons/temples, and depending on how you look at it, Palace of Twilight and Hyrule Castle may count as 2, 1 or 0. That said, I believe they were intended to be thought of as 1 or 2 dungeons. So, I will say that, in the end, I believe there will be either 6 or 7 dungeons.
I'll even make my predictions on what they will be:
Sky Temple (Obvious)
Forest
Fire
Water
Desert (Possibly Wind Style)
Mechanical Dungeon (Already pretty much saw it)
So, those are the six I think we can count on seeing. I also think there could be one more dungeon/temple, and actually think there's a decent chance at it. My guess for the final area, would be something like "The Dark Tribe Headquarters/Hideout". It seems like an interesting idea, to have a temple with about 3-5 boss battles as the final area, and then having the King of Darkness in charge. Perhaps this could be the Temple of Time. Maybe this would be the area where the Master Sword actually appears.