To me there biggest obstacle for using 4E for an exploration based sandbox campaign is the easy of leveling monsters. Bear with me...
Note: I am using the assumption that in this hypothetical sandbox, the difficulty level of an encounter area is determined prior to being encountered by the party and remains unchanged. For example, if the DM has pre-determined that the swamp is inhabited by trolls of a certain level, this does not change when the party explores the swamp, whether this happens at level 2 or level 8.
A large part of sandbox exploration is players making decisions about what are appropriate challenges. In older versions of D&D, this decision process was much easier as you needed fewer pieces of information. If you knew that the creatures you were facing were goblins and you knew there were six of them you could make a pretty good guess as to if your party could defeat them. If you knew that the cave you were entering was the lair of a large red dragon you likely knew that you were in trouble.
The ease of leveling monsters now means that there are goblins that can challenge a party of level 1 up to level 10 (for sake of argument) or level 1 appropriate dragons. The base line for making decisions about what your party can effective handle has been blurred to the point where only a knowledge-based skill check can give you the information.
The worst part is if you fail this skill check not only are you withheld the information about if your character stands a chance in the fight but you are now also doomed to a long, grindy combat that will likely not be much fun.
Note: I am using the assumption that in this hypothetical sandbox, the difficulty level of an encounter area is determined prior to being encountered by the party and remains unchanged. For example, if the DM has pre-determined that the swamp is inhabited by trolls of a certain level, this does not change when the party explores the swamp, whether this happens at level 2 or level 8.
A large part of sandbox exploration is players making decisions about what are appropriate challenges. In older versions of D&D, this decision process was much easier as you needed fewer pieces of information. If you knew that the creatures you were facing were goblins and you knew there were six of them you could make a pretty good guess as to if your party could defeat them. If you knew that the cave you were entering was the lair of a large red dragon you likely knew that you were in trouble.
The ease of leveling monsters now means that there are goblins that can challenge a party of level 1 up to level 10 (for sake of argument) or level 1 appropriate dragons. The base line for making decisions about what your party can effective handle has been blurred to the point where only a knowledge-based skill check can give you the information.
The worst part is if you fail this skill check not only are you withheld the information about if your character stands a chance in the fight but you are now also doomed to a long, grindy combat that will likely not be much fun.