Making the "Big Decision" to buy a boat always comes with second thoughts and introspection. Have you been able to speak with the owner, or only through his agent? If you get a chance to speak with him, (Or her) what do they say about the issues uncovered by the surveyor?
As mentioned earlier, you may have a tough time selling the boat in the future as it is. Any future buyer will uncover these things also, unless expertly repaired, which would cost a bundle, as you have said.
The broker is interested in his 10% comission and will always say you should buy. I have NEVER found a salesperson whose best interest is anywhere but their own pocket. I even have done the unthinkable, as far as selling a lovely 30'' C&C to a family with little to no experience. (I at least gave them three all day lessons "gratis")
You can of course back out of the deal based on your surveyors feedback. I doubt the current owner will accept almost a 50% reduction in selling price, based on the repairs
cited. DO NOT let any broker pressure you into ANYTHING. You have no obligation to them what-so-ever!!!!
From what you had stated in previous posts in this thread, you are looking for something that you can enjoy on your lake, and then sell in a couple of years. You should not be in a hurry. Do not succumb to the outside influences of those who do not have YOUR best interest at heart. Your surveyor was hired by you to give you a fair and honest representation of a vessel. He has done that. You are now feeling uncomfortable in the deal, and have the right to reject the vessel based on his findings.
Move on and find a boat that passes survey so you can sleep at night and enjoy your sailing during the day!