I am starting a campaign soon against skaven and empire or possible tk. I was wondering if the idea of a fully defensive army sounds good with a couple of bolt throwers, with elves, cauldron of blood, lots and lots of crossbowmen and some dark riders. Give me your opinions. Thanks.
Defensive armies can definitely work, but you have to keep in mind that, even though you're waiting for them to come to you, you need the charge. Getting charged both nullifies your high Initiative and makes you lose a lot of your attacks, which is another army advantage.
That said, the list you outlined seems pretty solid. I'd recommend some harpies for march blocking/machine hunting, and suggest that your crossbow uniits be 16 strong, but I definitely wouldn't argue your choice to give it a try.
