Depends on how the chewy center of the game - the story, the main missions - is structured within the sandbox.
If it's spread out over the entire world, as games are wont to do, traveling becomes an exercise in tedium. Even traveling through terrain pockmarked with "activities" becomes arduous if you have to pass through twenty or so "activities" on the way from Mission 1 to Mission 2.
But!
Imagine you have a wide open sandbox - 500 square miles, give or take; or even 5000, a la Fuel. Imagine that within these open regions (themselves home to a variety of "wilderness-y" gameplay experiences such as RDR's hunting/cougar-chasing/etc.) is a small, well-defined group of "hub locations" - cities, towns, what have you - that offer main gameplay missions. Suddenly, the game becomes two things in one: A semilinear adventure involving very little by way of tedious wilderness walks, and a wide-open sandbox outback where you can go hunt wallaby if you so desire. Think Oblivion if the wilderness was ten times as wide and twice as wild, and the cities were linked by in-universe instant travel methods. (silt striders?)
Best of both worlds? I think so...
If it's spread out over the entire world, as games are wont to do, traveling becomes an exercise in tedium. Even traveling through terrain pockmarked with "activities" becomes arduous if you have to pass through twenty or so "activities" on the way from Mission 1 to Mission 2.
But!
Imagine you have a wide open sandbox - 500 square miles, give or take; or even 5000, a la Fuel. Imagine that within these open regions (themselves home to a variety of "wilderness-y" gameplay experiences such as RDR's hunting/cougar-chasing/etc.) is a small, well-defined group of "hub locations" - cities, towns, what have you - that offer main gameplay missions. Suddenly, the game becomes two things in one: A semilinear adventure involving very little by way of tedious wilderness walks, and a wide-open sandbox outback where you can go hunt wallaby if you so desire. Think Oblivion if the wilderness was ten times as wide and twice as wild, and the cities were linked by in-universe instant travel methods. (silt striders?)
Best of both worlds? I think so...