I use a Webber Charcoal Grill to cook my burgers. I've found that if I want that intense grilled burger flavor, I have to use 70/30 grind, so that the fat drips down onto the charcoal, and put the lid on to concentrate that smoke, as smoke particle deposition is what gives a burger that characteristic grilled flavor. I once added extra fat, saved from a pork butt, and had so much smoke flavor that it created a very bitter and nasty burger. The 70/30 grid gives me just what I need. Also, salt seems to wake up the taste buds to other flavors, but not so much that you taste the salt. Finally, to reduce shrinkage, add one large egg to the raw burger, and mix it in. make the patties by hand, first making the burger into a uniform, 1/3 lb. ball, the flattening by pressing a little both between the palms of your hands, and pressing you thumbs against the sides to prevent the edges from splitting, turn a bit and repeat until the pattie is about 1/4 inch thick. Finally, the middle needs to be thinner than the edges so that the burger is uniformly thick when finished. The meat pulls toward the center as it cooks.
That should take care of your burger woes.
Seeeeeeya; Chief Longwind of the North