From Lyndro on the EQ2 Forums:

The new AA curve is mostly based on the amount of AA experience most people earn when they reach 90. For people who start up new characters (new players or alts), we’d much prefer they have fun playing the game rather than mentoring down to grind their way up to 280. This isn’t really compelling gameplay, and we don’t see a whole lot of value in perpetuating it. We’d much prefer that when the bulk of people “finish” (Finish is a tough term to define and is loaded and open to lots of interpretation, but I’m going to use it anyway) the first chapter of Velious content, that they spend their time in Withered Lands and Skyshrine working toward 92 and not building up AAs. For people that really enjoy grinding, that option is still there for you, you’ll just have to do it less.

and:

We looked at people who reached 90, so the answer to that question is somewhere between 0 and 100, inclusive. There are lots of different factors that go into this, and there isn’t a one size fits all solution, so we went with one size fits most. The AA slider is one factor of a few that changes it on a player by player basis (Some people tradeskill, some people explore to find every area in every zone, some people try to complete every quest, and some people try to get to 90 as quickly as possible). We had to look at time and the group. Picking out individual factors just muddies the data after a certain point.

Commentary — Why Did Low-Level Grouping Die?

The biggest reason why level 20-80 zones are abandoned or people do them solo is…

If you’ve been planning the mass extinction of Rays and Bulls in the Hole to grind out those 50 shiny new AAs, some ice water has just been thrown on that idea…

From Waters on the EQ2 Forums:

We’ve been watching where folks are playing and keeping an eye on how experience and alternate advancement gain is going since Velious launched. While we make every effort to balance the game during the beta testing period, we sometimes see new information on live servers, and need to make a change based on that info.

Alan “Brenlo” Crosby has announced some tweaks to the Experience Curve in EQ2 that went live today (January 20th, 2010):

Hey folks,

I wanted to pass along some news that you will see on the live servers tomorrow.  We have adjusted the experience curve in EQII.  We have done so for a number of reasons;

1.  It really wasn’t a curve before, more peaks and valleys.

2. Some levels had some very crazy and erratic peaks while others were far too fast.

3. We needed to adjust the curve overall for the addition of 80 to 90.

What will this mean for you?  You may see your bar move a bit when you log in after the update.  For most of you it will move forward, for some it might shift back a little.  The rate of progression from 1 to 65 will be the same in terms of gross XP needed but the level progression will be smoother.  We have increased the speed from 65 to 75 and this is due to two changes;

The required experience was lowered as it was actually harder to get from 65 to 75 than from 75 to 80.  Now it is in line with our expectations of speed of progression.

The quests in that that range will now give more experience as they were slightly behind the times in terms of XP rewards.

We hope you notice the smoother rate of progression and this removes a few bumps in your leveling.

Thanks all.

and further from the January 20, 2010 Patch Notes:

We have taken a look at the experience required to gain levels and made some adjustments. Leveling from 1-65 will still require the same overall amount of experience, but the experience required at certain levels has changed.  There were certain levels that required much more experience than others, but now the progression should be much steadier. Leveling to 65-75 should be a bit faster now for two reasons.  The first is that required experience was lowered some.  The second is that quests should give slightly more experience in this range now.