Dr. Awkward said:
I think you'll go planar before 10th level, at least in little ways. Some people have suggested that there will be tiers of difficulty for getting to various planar locations. Feywild? Dead easy. Shadowfell? Harder. Elemental Tempest? Heroic, but doable. Abyss? Epic.
Why do I think so few people use the Great Wheel? Not because it's not interesting, and not because it's canon-heavy. It's easy enough to pick up any book on the planes and just make up locations based on that. The problem is that planar travel is a high-level thing, and I think that many people prefer to play lower levels than that. You have to be a 9th level cleric or a 13th level wizard to cast it, and there aren't many places you can go that aren't horribly dangerous anyway. Once you're comfortably 15th or 16th level, you can handle a little jaunt into the Abyss, or go on a mission to rescue someone from Carceri. I think that the new system is intended to allow lower-level parties to go exploring other worlds if it suits them.