If you just hung the gate on one set of these it would be a problem. Also if you just used one bolt to hold the strap to the gate it would be a problem.
With that said if you build your gate as a rectangular element with proper cross brace so that the gate itself keeps its shape and then mount the straps to the gate with two bolts each you will not see gate sag due to the larger size hole in the strap versus the size of the post on the L-bolt.
You should have 2 or even 3 of these hinges to install on the gate which can be adjusted to correct the slope of a loose fitting pin. However if the pin is way too small I would check to see if the right hinge pin piece was supplied. Remember the top hinge pin is usually installed facing downward so the gate can not be lifted off reducing tour security. All others face up.