I want the overworld to be similar in concept like it was in aLttP and MM. They had the best overworlds so far in the history of the series, which is one of the many reasons those two games are my favourites in the whole series.
Let's look at MM's overworld for now: Instead of having only small corridors that connected the overworld parts in OoT and TP, MM's Termina Field was transitional between the differently themed areas (canyon, beach, ice, swamp). There were some sort of corridors too when you went to the areas proper but they were much broader and filled with many enemies and characters. The enemy/character and detail density of those places was much higher than in any other 3D Zelda to date. Another cool thing which is already confirmed for SS - smooth transitions between overworld and dungeons - was already very present in the game: just think about places like the Deku Palace, Gerudo Fortress, Bottom of the Well, Ikana Castle and last but not least Stone Tower, an interesting detail in the latter case is that the music doesn't even reset when you enter the "actual" Stone Tower Temple which BTW is my favourite dungeon in the series.
From what we've already seen of the overworld (fx the E3 demo), I'm very confident that SS will develop further in that direction - a very dense and more realistic overworld with lots of secrets, grottoes etc. instead of a mostly huge, empty and unpopulated taiga-like landscape which was in TP (which of course was still a very great Zelda game).
Oh and I forgot to add I'd also like to see big towns with lots of stuff going on which changes depending on day/daytime/game progress like Clock Town but also smaller villages like Ordon with lots of sidequests and items, a good comparison would be the earlier Final Fantasy games.