It needs to be reevaluated by the hired game testers (Unless that's us) because some lines tend to be too long and forced in some situations (ie. female characters taking fire, running into smoke, etc.).
Voiceover from Insurgency seem to carry more weight whether they are taking fire or even then situations become more relaxed. Some examples include "RPG RPG!", repeated "no"s when suppressed, casually saying "reloading" during relaxing situations while having intense phrases when reloading during firefights. DOI voices when running into smoke felt more real, coughing and grunting for a few seconds.
That said, I find voiceover in I:S to be good in other parts. Some examples are calling for the observer/commander, telling whether it's MG or sniper when taking fire, saying religious phrases from time to time.
My suggestion is try to take the best of both games as references for I:S voiceover reevaluation. Make voices in specific actions such as reloading and calling fire support in different occasions (ie. relaxed, tensed). Or just about anything that gives weight and in-depth characterisation to the voices.
Overall, it's the little things like voiceover that gives depth to the game and to the character models we choose. Yes, it feels like I'm nitpicking; but this is just my opinion. The decision is up to NWI, of course. And most voiceover in I:S is good, just that some needs to be reevaluated. Feel free to give your comments. I'll give more updates in this thread in the future.