I'm using it for transcendence for my wol build. I have found that I am dying not by getting nuked but by not gaining hp back fast enough. so lets not have this turn into a heal monk stat fight. thx.
Well, I wanted to do a Shi Mizu build and it happened that almost every ancient item I've augmented has the bonus as a secondary (also some pickup radius, which is even worse for Shi Mizu). So there is that
it's not like Istvans are completely mandatory to make a supp monk work. But overall you're right of course
well, so it's not possible on pants and belt either.
on offhands it's also possible. like sources and mojos for example. So should be possible on shields too.
so now we have a complete list of which items can and cannot roll it as a secondary affix
the stat cannot be rolled on weapons, helms, bracers and gloves. that's what I can tell for sure.
but need some zmonk expert to answer your question for all possible items.