I'm pretty much torn on this issue. Sometimes huge open world games scare me... and it boils down to the fact that I hate to miss anything important when playing a game. For example when game worlds were relatively small and linear and I was exploring a dungeon in an RPG i might come to a fork in the road. Next I would try to determine which path might advance the story or take me out of the dungeon and which path was more likely to have a secret chest, item, weapon or a character/boss to encounter. If I choose one path and saw that was taking me further away or leaving the area, I would turn back. I would always try to explore all paths before preceding so as not to miss anything.
In an open world game it is much much harder to explore everything and I always have the feeling that I am easily missing stuff. Anyone able to find all the bobble heads in fallout 3 without a guide? Probably not.
That being said I also have problems with an RPG being too linear. I feel like an "RPG" needs to have some exploration whether its exploring towns or a world map. Personally I loved the world map back in the PS1 days with FF7, FF8, & FF9. Gave me the excitement of basic exploration to find new places and the freedom to wander around and ability to go back and revisit places later on (in a airship, on foot or by chocobo) to get something you may have missed. Those were the best.
In FFX, I was pretty disappointed with how linear that game was. You basically just walked on a path for the first 3/4's of the game until Zanarkland. It was too easy to find the secrets, just look at your map and you see a small branching dead end path to the left. Oh, I bet there is a treasure chest there. Sure enough there was.
I know I would knock points off Final Fantasy XIII review score for being little more than a straight path for 30 hours, but hopefully the story will still be good enough to keep me entertained. Final Fantasy X has my 3rd favorite story in final fantasy game so I still was able to enjoy it. The narrative was much tighter as a result.
In conclusion, if I can go back and and return to areas that I missed in a open world game then I'm okay with it. And if a linear game delivers excellent pacing and story than I more than fine with it. However, if I had to walk everywhere in Fallout 3 without fast travel I may be signing a different tune today about open world. I don't like to waste that much time wandering around in game.
[RPG's I'm playing in the near future: Final Fantasy XIII, Red Dead Redemption, and Fallout 3: New Vegas]
