On paper suppression seems like a really fun and useful mechanic for dealing with groups of ranged enemies. In actual gameplay, in my experience it has felt lackluster, less like a mechanic that you intentionally use tactically and more something that just happens sometimes without the player even really noticing.
There are a number of reasons for this, one being the fact that it just straight-up doesn’t seem to work correctly half the time, especially against enemies that aren’t near an unoccupied piece of cover.
Another being that a lot of the automatic weapons that are theoretically intended to be used for suppressing fire chew through ammo too quickly to be worth using that way.
A third being that suppression doesn’t actually seem to last very long, enemies pop back up seemingly within only a second or two of when you stop shooting at them.
But I think probably the biggest thing, for me anyway, is just that it’s very hard to see and appreciate the effects of suppression amidst the chaos of normal gameplay.
I often have difficulty telling if an enemy is being suppressed or simply shuffling about as a part of their normal combat behavior. When there are hordes of melee units on my screen as well as specials and elites in addition to groups of ranged enemies, it can be difficult to really see how much of an effect your suppressing fire is having, and sometimes even to keep track of if the enemies you were suppressing just a moment ago are still there, hidden behind cover, or if they’ve been killed/moved somewhere else in the brief moment your attention drifted elsewhere.
Even without any other changes, I think it would go a long way to just give the suppression mechanic better visual feedback. In particular, highlighting or putting an icon over the head of suppressed enemies so you can easily see the effect you suppressing fire is having would make utilizing suppression enormously more fun and satisfying, in addition to providing much needed visual clarity.
Whether or not suppression needs changes mechanically, it definitely needs to give the player better feedback so they can better appreciate the effect when it’s happening and feel more satisfaction in using it.