Pretty much the title! While pretty much any other shield affix provides useful stats - be it health, resists, block chance / damage blocked - this one only provides a bit of fire damage and OA. If you’re not going retal, anyway. Moreover, Temper doesn’t scream “conflagration”. It would’ve been a better fit for something like “Blacksmith’s” or “of Hard Steel” - or something like that, if such affixes were in the game.
So please consider changing it to maybe Flame Touched, Thermite Mine, or maybe even Heart of Wrath. Thanks!