Consider we already outlevel content in the beta, I think that fear is pretty non-existant. And XP will be cut. It's kind of silly to have a lvl 8 boss while you gain 11 lvls easily doing stuff around the world.
Oh, I agree there are definitely problems with pacing and challenges because of level differences, although that's the sort of problem that's going to happen when you allow players the freedom to explore different areas in any order and populate those areas with content that is of a specific level.
I would like to see some sort of level scaling at work, where encounters are raised up to the level of the party. They don't have to be scaled down to the level of the party, however, meaning it would still be possible to wander into areas that are extremely challenging (or downright deadly).
I personally don't have fun facerolling content, and get very bored when a level superiority over my opponents allows me to breeze through a battle. Anything that can be done to remove that problem without necessarily restricting where I can wander is something I can probably get behind.
I don't think simply lowering XP across the board is the answer, however, as then you're basically demanding players consume all content just to scrap enough XP together to remain effective, rather than the content they choose to participate in. You also can never tell when a player is going to go the "evil" route and kill half the town (after doing their quests), at which point you're faced with a player who has (once again) accumulated too much XP and trivialized many of the battles awaiting him.
