Both his son and posts here talk about Holliday having a good track record of getting WR to the NFL. In the last 8 seasons (BYU WR coach, Utah WR coach) he's had two WR make it to the NFL as UDFA - Jordan Leslie and Tim Patrick.
That's not a terrible success rate by any stretch, but it's also not an astounding record of success lately.
I don't know anything about the firing and whether it was or wasn't justified, I'm just saying we should settle down and stop throwing hyperbolic claims around