I have remarked once or twice before that modern young writers just don't know they're born. They now have access to so much information that just simply wasn't available 40 years ago.
For instance -- and it is one hell of a for instance -- the agent who blogs as Miss Snark apparently invited people to send her synopses for an online critique. And she spent a week going through them and posting the results. Here's the link. If the page takes a while to open, that's because it's a long page. There's an awful lot of work involved. And the post you're looking for is dated 1 January.
So, there you have it. A real live working agent's take on 100 synopses. Well, 99 actually. There were 107 submitted but various got dropped for various reasons .
Now if you can't learn something from that I just don't know what to do for you.
M.J. Rose noticed this before I did and provided the link. But then she's smart like that.