I likes it, it'll feel much more like the final fantasies of old where exploring rewarded players with little secret areas.

Only problem I see with it is this is an MMO so once it's been discovered it won't stay hidden for very long and will simply become 'just another dungeon', which is a shame, but the first day or so of it's release will be exciting as hundreds of players all go dashing around trying to find where it is then hopping onto the forums in hopes of being the first person to shout "I FOUND IT! "

Little hidden areas like super-pretty caves hidden behind bushes or waterfalls and stuff have always been kinda fun though, I'd probably spend hours riding around on my chocobo trying to find them and take screenshots.