Saxon are pretty cool. One of the more overlooked NWOBHM bands, and partially for a reason; they certainly didn't bring up anything as groundbreaking or innovative as Iron Maiden, Venom, etc. did... but what they do, they do well. Which is play Heavy Metal.
But they predate Saxon by a decade (give or take a few years). Judas Priest were from the first wave of Heavy Metal, releasing their debut just four years after Black Sabbath. So yeah, you're right, but you sorta have to put things into perspective. Priest belong to the guys who invented the genre, Saxon belong to the guys who gave it a new breath of life.