I absolutely loved it. Mainly because I love the ocean aspect and in real life love water and stuff. I hope Skyward Sword has a huge open world. Perhaps tons of Sky Islands in Skyloft to fly to on your bird. Same as the Great Sea but with flying.
I just like to blow stuff up right in the enemies face, jump the water, fish for treasure, make a complete map and battle a giant kalamari that vanishes and spews out rewards or a fairy that grants you power ups.
But even before then it was great it was soo epic on the high sees, cold raining or silent nights, monsters of the deep, uncharted islands, pirates pirates pirates everywhere. it was just a really cool feeling sailing away.
I really liked it when I started playing; it had this adventurous feeling to it and it seemed the possibilities were endless. But after a while it got kind of boring, and I dreaded having to sail all the way to the next island.
I hated the sailing so much, mainly because there is so little to do and to complete everything in the game you need to sail the same bits of sea over and over again. For example, doing the Goron trading quest meant sailing the same stretch of sea over and over again as only one of the islands that had a Goron on it could be warped to. People talk about Wind Waker having a large overworld, but if you take out all the bits of empty sea then actually there is not much there. For me, Zelda should be about exploring a location the first time you are there, but then being able to navigate quickly afterwards, Wind Waker doesn't really do this (Ballad of Gales can only get you so far, you still need to sail quite a bit to get to most islands).
I like it, its awesome.. your imagination can go wild with what is underneath your boat.... that and lets face it the open ocean is sort of freaky... Makes you wanna cling to that little boat like a little mad Hylian
My favourite part of the Great Sea was all the different islands. It was fun to explore everything (the fact that you could chart everything only added to the experience) and it was amazing to find new places to go. When you simply went from point A to B it did occassionally feel a bit slow as the distances could be huge.
But while the size made things slower it also added a lot of depth to everything! It was huge and there was a lot to find. But I get it when people say they didn't like how much they had to sail. Sometimes there was enough time to go and make coffee, but personally I think Great Sea fit WW's atmosphere and cel-shaded style perfectly.
I love how they incorporated it to be over Hyrule, and the people on the islands don't even realize that the land of their ancestors is directly beneath them. I do find it curious, though, how you can snatch treasure with the Grappling Hook if the land is so far below the water... And also what might be holding the water in place, keeping it from completely submerging Hyrule.
Probably the Triforce, because King Daphnes Nohansen Hyrule placed his hand on it and wished his kingdom be flooded in order to save it from Ganondorf
Aside from my crazed theories, I loved the exploration, despite the longish sailing, and the uniqueness of each island. Stopping to fight enemies on those watchtower platforms was also a fun pastime, especially when I could bomb the enemies out of them.