I think the subject line says it all, but if I may elaborate:
One of the great things about Eberron is the whole idea of alignment and ideological affiliations being separate. You've got Priests in Good temples who are just as Eville as can be, and vice verse. The lines of loyalty and ethics get blurred.
I understand it's a 'family game,' but consider the fact that even 'Sleeping Beauty' and 'The Lion King' have Eville characters.
I dont think the bad karma of being Eville is avoided by not looking at Eville, but it becomes evident as the consequences of Eville are observed. Just because people could play Eville characters doesn't mean they'd run around anymore willy-nilly than they already do. Nor do the Good aligned characters in the game always do the right thing by each other, anyways.
Part of the whole Fantasy genre is the struggle between Good and Eville, and which one the character DECIDES to be.
Heck, I don't even like playing Eville characters, myself! I just think it's preposterous that this most basic of choices isn't part of creating our characters. Personally, I'd find it more INTERESTING if I have to keep an eye on my buddy the Eville Sorcerer.
Just sayin'.