My literary agent knows what prepositions are. And she doesn’t care if I end sentences with them either. ;-)
But boy howdy does she ever care if I use too many adjectives! Lol. Or if my story is boring.
I will never forget one of her first emails to me. She got my attention when she said, “This story is fast-paced and exciting, but tone it down, Purple Prince. If you need three adjectives to describe something, you’re going to turn off your readers. Clean it up!”
Oops.
I had to really work at my writing style after reading that. And I think it made a big difference for the better.