It's a totally weird phenomenon, but I've had more authors hire lawyers to read the Author/Agent Agreement they sign with me than I have authors who have hired lawyers to read the publishing contract. Now, I'm not saying you have to hire a lawyer to read the publishing contract, since that's one of the things you pay your agent to do (read and negotiate), but when you do I find it odd you would hire someone to read the least important of the two contracts.
I appreciate that you trust me to negotiate a strong contract on your behalf, and I will certainly do that, but what I find most disconcerting of all is the recent realization that so many authors are signing these contracts without reading one word of either of them. Isn't that mom lesson number two? Right after saying please and thank you, aren't you taught to never sign anything without reading it first?
No matter what you think you are signing, you are responsible for it once you sign. Therefore, when getting your contract, it's important that you are aware of what it is you're committing yourself to.
Due dates? Those are your responsibility. That means if you commit to a due date that seems "absurd and ridiculous," well, you've committed to it, so if it is "absurd and ridiculous," maybe you need to discuss that with your agent and editor before actually signing the contract.
Manuscript length? The publisher expects your manuscript to be a certain length, and if you think it's too short or too long, discussing that with your agent and editor before signing is better than trying to argue the point with your publisher well after the fact.
Materials? If the contract says you are responsible for providing 25 pieces of artwork, permissions for copyrighted material, an index, or your firstborn child, you will be responsible for supplying that.
My point? Read your contract and ask your agent about anything that you have questions about. That's what you pay her for. I get that a 15-page legal document is a pain to read and can make your head spin. I read them almost daily and sometimes my head spins, and yes, I always think they're a pain to read. But they are important and they can be negotiated before you sign them. It's not so easy to negotiate after they've been signed and counter-signed and you realize you actually like and would like to keep your firstborn child.