I've no real idea what you're saying here, but I'll try and attempt a response. I'm not sure if you think that being Infuriated is the same as being under the effect of Unchained, or if you just mean that when you use a 5 stack move (Inner Beast or Steel Cyclone) that they ignore the damage penalty. The latter is true, however both are bursts of high damage - after they've done their job you have to slowly build back up to your 5 stacks again while all your abilities are doing 25% less damage. Unchained, on the other hand, removes that penalty and (especially coupled with Berserk) will net you higher damage during the course of that 20s than you would gain from the burst with IB/SC. In terms of threat and damage, Unchained beats both as long as you get the full use out of it. I see you play Summoner, so think of it as a difference between using Ruin 3 for a big 1 GCD of damage or one of your DoTs which takes awhile to fully work but will give you more damage in the end. Not the best comparison, but hopefully that clears things up.
In terms of adds spawning in a boss fight, it's worth noting that Unchained should be used at the start of the boss fight (Infuriate before you pull or have 5 stacks ready from previous trash -> pop Unchained -> Tomahawk -> etc.) so any point where an add would pop up you've probably already ran through the full duration of Unchained and it (hopefully) won't be back up again before the next trash pull. You also say "spamming overpower but then that would be a waste wouldn't it" - however, it's worth noting that @ 3 mobs OP is your strongest GCD (360+ potency every. single. GCD). In terms of Wrath usage, it depends on the situation - if you've got Unchained available, it's insanely powerful as it allows your OP spam to be powered up by Berserk + Bloodbath. If Unchained isn't available, you just decide between Steel Cyclone (damage + snap aggro on multiple mobs) and IB (20% damage reduction, so good when you're running weaker CDs and there's a lot of damage incoming).
But. Yeah. Hopefully that clears things up maybe? I'm not sure if your first language is English or not so I'm not trying to be offensive here but I just had a difficult time putting together your points.