This devotion is literally impossible to see in fights. I never know if I already pocced it or not. The only moment when I see it procs it’s vs. training dummies, because I only try to check if it even does work.
I never, literally never see it proc on hero+ monsters, I mean it surely does proc, because I have it attached to my skills and it procs on dummies, but the green flash is so small and hard to see that it’s impossible to tell if something actually happened.
I know you get a broken shield or whatever right on the enemy, but it doesn’t work at all because I apply other RR first. My settings are all set to max, so this is also not the issue.
Suggestion: make it more visible by increasing the effect colors, making it bigger in height or increasing duration of the visual effect itself. Right now it just flashes for like one second or even less, which is not noticeable at all.
I totally understand what you are saying. But think about it: what would change? I mean, you wouldn´t wait until you see the proc, and then start really dps-ing, or whatever, right? Trust me, acid spray does indeed, if you have bound it to the “proper” skill proc very often. In fact I very much like how it works, bind it to a skill and forget about.
This is the one suggestion that I totally agree (even though idk how to fix it) but just really don’t care because I know for sure that Acid Spray is up 95% of the time.
I mean, this is true it’s up 95% of the time, but if you want to cast a solid nuke for massive damage, you kinda don’t know when. Sure, that’s still not a big deal, but you sometimes want that max hit damage on your screen. 
All other devotions are visible, some by having a huge visual effect and some by having a persistent effect if you chain your skills right, but you still can see them in a way. You basically forget about Acid Spray all the time. I even sometimes go for additional “x reduced resists” because I am sure I don’t have that devotion, while, in fact, I have it. The only reason I remember (in this situation) that I have Acid Spray is the level up of this devotion.