I hadn't read much on the game before I started, and I kept calling that there would be a PH dungeon in the game (I just had a feeling, I'm not sure why), and when I finally got to the Silent Realms, I was like, "There it is!" and I loved it. I haven't done the Eldin one yet (just finished the Lanayru one), but I really enjoyed the two I've done so far. They are mandatory, but you get cool items from them anyway.
lolwat. What part of the silent realms has anything to do with anything in PH? More to the point, how do they not scream Tears of Light from Twilight Princess?
Don't get me wrong, they are awesome. Easily the most post-game time I've spent is on Silent Realm time trials.