By feedback, I don't mean a critique of your query (like the work done over at QueryShark) rather it I mean feedback on why I didn't ask for a full. (I'm using myself here, but it applies to all agents.)
Here's why you don't want that:
I pass on 98% of the work for which I'm queried. I generally use a form letter.
Sometimes a writer will respond (politely!) with a well-concealed howl of frustration: "but why??"
Because I am one of the dwindling number of agents who actually replies to all queries, any response from me would take on more importance than it should have. I'm merely one of several (dozen I hope!) agents you've queried. You heard back from me, so you replied to me.
But all those other agents passed too, and maybe for different reasons.
And while it's entirely true I'm brilliant and perceptive and have the best taste EVER, I also have passed on things that have gone on to do quite well.
In other words, I don't have a lock on what's going to sell.
Thus, your query may very well resonate with an agent other than me, and if you start tinkering with it to match my tastes you may very well end up trying to make cookies out of cake dough. I like cookies, and if your manuscript is cake, it's going to be delicious to the agent who wants cake.
(Oh who am I kidding, I like cake too!)
Getting feedback on formatting, and how to get your plot on the page, and what kinds of comps are effective: that's objective feedback.
What's subjective is I often pass on darn good queries when it's a book in a category I don't know well (romance, women's fiction, fantasy all qualify here.) I tell people to query me on anything, but that's because people often get their categories wrong, and something you're calling dino porn may in fact be a top notch thriller. I rep top notch thrillers but not dino porn.
Any feedback from me on those categories isn't valuable, and it's potentially very harmful.
And I don't like all thrillers either. Or all crime novels. Or all of any category. If I'm not the right agent for your book, I'm probably not the right agent for telling you what to fix about the story.