In GU49, EverQuest II is going to dramatically lower the experience curve required to level. Right now, apparently, it takes an average of 260 hours to get to level 80. However, most people consider the end game to be the only true part of the game. After all, that's where everyone else is, and the most fun parts of an MMO are the parts where you can play with other people in tactically interesting scenarios. Levels 1-79 becomes sort of a really long drawn out tutorial. Granted, we need to take some time to learn our characters, but do we really need a 260 hour long tutorial? Every time they raise the level cap, that tutorial effectively increases in length (fortunately, SOE decided not to increase the level cap for The Shadow Odyssey), making things worse.
There are two problems with the wide level disparity:
1) high level players who simply want to try out the end game with a different class (or race) but don't want to grind through the same old content all over again
2) new players who find the world empty because all the veterans are playing the end game
Sony's decision to decrease the time it takes to get from level 20-70 (by about 64 hours!) is a pretty bold move. The proposed change to GU50 that allows each level 80 to give the player a +10% XP bonus to all their other characters is a great idea as well, allowing us to reroll our characters, and still take a decent amount of time to learn then, so that leveling an alt doesn't become a chore.
Some discussion on MMO Nation referenced AGDC roundtable discussions that, among other ideas, proposed 'instacharacters' (like in Dark Age of Camelot /level command - or the Death Knight in World of Warhammer, which starts at level 55). That sounds good to some extent, except it only addresses the first problem. It would probably make things worse for new players or anyone who chose to level up from the beginning.
At least with Sony's solution, new players have a chance of running into someone leveling back through that 1-80, even if they might be doing so faster.
Maybe there could be other alternatives that help address both issues? Perhaps people could earn a new kind of point system, such as "social XP", when mentoring players, or assisting low level players with quests or defeating named monsters, in addition to whatever benefits they normally get (such as accelerated achievement XP). Maybe players who don't have a max-level character on their account would have the option to flag themselves as "newbies" to attract the attention of more experienced players who want to earn social XP?
Social XP could be an account-wide pool and be used to purchase accelerated leveling (or bypass levels) for other characters. Or even other bonuses, such as unlocks for exclusive new races or prestige classes. That would encourage players to use their existing characters to help new (or rerolling) players to power level their offline (or future) characters.
While skipping or accelerating through levels for veteran players is a great idea, it does have some impact on the rest of the game, and a healthy game needs to retain the ability to attract newer players. That isn't possible if everyone just auto-rerolls high level alts or rushes through the old content in the optimal fashion as quickly as possible.