Oh, I feel like we had Dire on a magical beast not long ago. But it's probably easier just to go with Iron Will if we don't remember.
If I remember correctly, the most recent case of Dire Magical Beast syndrome was the Elite Giant Rat, aka the Ratbear.
If we're boosting the save, go with the bonus feat. But you're right, I don't see a need to codify a typo.
Actually, we preferred to simply correct its Will save to its proper lower value.
Updated.
Alll done?
These things won't be going after the high HD Outsiders with loads of SLAs. Really, an imp's suggestion DC of 15 is about the worst it would face, and it could beat that about 35% of the time. So it seems ok.