Map exploration experience should be reward to new players. Not to players who already have all their jobs maxed out. For one thing the new players whom are just starting are taking a risk that capped players wouldn't. So it's much harder for them. Thus they are more deserving of the experience reward.

ARR isn't just for those who've been playing. It's also for players starting fresh.

Honestly though, I don't see how ARR could work at launch unless *everyone* playing was also "reborn" at level 1. They would have to loose everything but their achievements. ARR is the one time when people are likely open up to the game, or return to the game after trying it and hating it. You can't have two groups, one level 1 and one level 50 exploring the same open world together. It would be like if FFXIV allowed FFXI players to keep their jobs, levels, and whatever else for their FFXIV character.