I like to add 1/2-1 t cumin to our version. It adds a little bit more smoky flavor. If we were all fans of things with a little heat, I'd add some chipotle powder as well.
My sloppy joe mix was a bit on the thick side so I added some water. Be very careful when you do this because I went a bit too far in the other direction, adding too much water. This just made our joes extra sloppy. I could have let it simmer for longer to let more of the water evaporate, but I was too lazy and hungry to do that.
Pumpkin Sloppy Joes from Taste of Home
In a large skillet, cook beef, onion and garlic over medium heat until meat is no longer pink; drain. Stir in the pumpkin, tomato sauce, brown sugar, mustard, chili powder and salt. Bring to a boil. Reduce heat; simmer, uncovered, for 10 minutes. Serve on buns as you would good old Sloppy joes. I like mine with cheddar and lots of dill pickles!