As per the discussion in the Sentinel thread re Devouring Orbs animation. I would like to suggest the following:
It is difficult to tell during normal gameplay how many active devouring orbs are in play. While possible, counting spinning orbs is tricky at best but this gets progressively more difficult (to impossible) as the action on the screen gets busier with overlapping AoE effects. This is such an issue, that it promotes auto-casting or at the very least, spamming of the skill because you have very little way of knowing if its maxed out or not.
The Maelstrom skill of the Primalist has a status icon on the bottom left above the skill interface that shows 1) if the skill is active and 2) has a counter for the number of maelstroms in place.
I would suggest that a similar staus icon be implemented for Devouring Orb.