Without more information, I really can't get too excited. The concept sounds cool and all, but there has to be a bit more than just, Whoa big desert. If there are no enemies and no overall plot, the game better bring a lot of other things to the table in big doses.
I'm talking about collectibles, intriguing and varied puzzles, awesome landmarks, and customization (Maybe different style of robes or hats, maybe even costumes). For me, I don't support developers that think they can get lazy because they have a unique concept or game.
Journey sounds like its going to bring the immersion, which I'm always a fan of. So, I'll wait before I get super happy about something that has virtually no information..