There's a developer diary about these changes, but basically, they acknowledge that the steps of the epic questline which require a group can be frustrating to do these days, since LOTRO is a mature game with a predominantly max-level player base, making it often difficult to find a group to do these quest steps with. So, they have reworked all of volume I, apparently, so that every step which previously required a group can now be done either in its original state, or in a solo version where you are heartily buffed to make it possible.
I've written before about being frustrated when looking for a group for the epic questline, and how I was looking forward to this change. This definitely makes me want to re-subscribe to LOTRO for a spell. Well done, Turbine! Now I just need more hours in the day to fit this in alongside Atlantica (still having lots of fun there), WoW (my guild is now up to the Lich King in 10-man, and only a few bosses short in 25-man) and everything else (like spending more time on my Darkfall trial).