HoldinHolden, it sounds to me like your platform is significantly bigger than mine, so I'm surprised to hear you've had trouble with the platform aspect. I've had half a dozen articles published and been interviewed in magazines and been on one documentary and one mainstream news program and one radio show, but don't really have much of a following on blogs or anything--no awards either, and definitely no news show. I would think the people who want you to have a large platform just want to see evidence that you have a built-in audience, and you seem to have that in spades!
My agent definitely works with me. When she called me to offer representation, she first discussed with me what she had in mind for the publishers she wanted to send it to and made sure we had the same vision, so that was a great start. And then she basically went through my proposal and asked me to rewrite certain parts in active instead of passive voice, and suggested a reorganization of the order of my proposal parts. She never sent anything to an editor without asking me first. And when editors give her feedback or ask questions, she asks me what I think instead of answering them on my behalf without my input. She more or less lets me run the show but if I ask her what she thinks she always gives me her own perspective too--it's just really refreshing that she always asks me for MY thoughts.
I should also make it clear that I know, based on the way she talks about my book, that she understands why it should be published and can express why she thinks it's important. It's not just about "this will sell." It's about "this will help people." She seems to have a very good balance between knowledge of the job and passion for the material that works very well for her. I'm very happy with how it's working out so far, and she's approachable, so when I do accept an offer, I'm confident that I'll be in good hands.
The proposal part that I've seen agents complain about most is the marketing ideas--because people who don't know what they're doing tend to suggest really generic or unrealistic options, like "my book is perfect for a coffee table" or "endcap positioning at bookstores" or "I'll do television interviews." You have to demonstrate that all the ideas you have for marketing are realistic and within your grasp, preferably featuring connections you already have and specific places your ads, appearances, and promotions will be a good fit. With no knowledge of what kind of stuff you're throwing out there, I'm pretty much assuming you've got this covered because you seem like the kind of person who has been around the block enough to know how exposure works, but that's just for you to keep in the back of your mind. Agents will appreciate seeing really specific marketing ideas and evidence that you have the connections to make them happen!