I posted the following  a month or so ago on a different forum topic, but after this weekend I decided to re-grade....

Officiating Grades from worst to best IMO:
MLB - F-

NHL - D+

NBA - D

NFL - C

 As of today, Monday, April 27th 2015:

MLB - D+

NHL - C-

NBA - F-- (I have to be somewhat realistic as there is no such thing as a G)

NFL - C