Believe it or not, I've speculated on this before in my Elven Ranger analysis.
Analysis of the Elven Ranger
Are you using Horizon Walker? Horzion Walkers, should, in my opinion, be Lawful. They are the Grey Knights of DDO and would need the mental discipline and training of a lawful alignment to succeed in their battles against interplanar creatures.
If you are not using Horizon Walker (or disagree with this reasoning) then Elves, especially Wood Elves, are thematically considered to be Chaotic (Good).
Gaming note: One of the current end-game bow options, the Chaos Bow, gives a negative level to Lawful characters.