It's really cool to have a large environment with places to go, but who likes to scroll around? Actually it was a positive point in GameDev Story that all the action happens on one screen. Also while playing The Sims I also remember being perfectly happy that everything happened in the house, going outside didn't seem that much fun even when it was possible in later games. On the other hand, in that island survival game it was a big part of the fun to be able to explore outside.
So why does it sometimes work? Where's the fun?
In The Sims going to places wasn't fun, because it didn't feel like you can advance in things like career path or relationships by doing it. It wasn't really even part of the game if you think about the game as a set of rules to take advantage of for improving on the stats.
What if in the island survival game the player was limited to one screen. All the food gathering and raft building would happen right there. It might work, walking around really wasn't all that much fun in it, but discovering new places was because they often had very significant effect on the player's success in the game. For example discovering a new source of food. In The Sims places had no such significance.
In GameDev Story you actually can go to one place, the gamedex expo. In the expo the player can get fans for the game he is making, but it isn't clear if it really affects the success of the game. It feels unimportant. Also like in The Sims, it takes a lot of player time to go out with no clear benefit, not really that much fun.
Conclusion from this rambling seems to be that exploration is fun only if there's a clear benefit to the player.