Ok here's the problem.
I have some friends that one time or another they play ddo. Every time we had the same problem. I only play one toon (as they do because normaly is his first one), but everyone have his own work and play schedule, so normally we are not on the same level range. But sometimes, mainly the nights, planets align and we can log all together. We can just help the one we lowest level because we will eat all the exp for the level exp penalty and the low level one cant come with us into a high level dungeon.
I will like some mentor system to see that fixed. A system that allows us to play together independent from the level ranges. It doesn't need to be the better way to level, but at least that worth the time instead of eating all the xp of my friends.
I know, its complicated because Turbine cant just remove the xp penalty of peeps will abuse it for the TR's, I'm sure they can come with some way to help peeps in the same situation i am.