I just came back to LOTRO last month. I snagged up the most excellent gaming deal I've heard of. The full game, along with both expansions, plus a one month subscription for just $9.99. The deal is over now, unfortunately.
Anywho, I came back and logged onto an old character that was lvl 45. In my next few days of playing(5ish levels worth) I couldn't have seen more than 10 people. This was probably due to most people being in higher level content but to me it was just unacceptable. I ended up switching servers to the most populated one and from level one I saw a huge increase of people. It's actually possible to get a group for most group quests. Sometimes a little patience is needed though.
Content wise I've read some gripes on the forums but for me there has been enough.