Nothing else matters next to this. Taken together, someone could look at all the potency increases and think "hey, those are some all around buffs for WAR" but the truth is, the loss of 10% damage on SE means none of those potency buffs are actual increases to damage. At best you're looking at a loss of ~.7% damage (this is on Overpower) and at worst it's a loss of over 7% damage (this is on Fell Cleave). This is on top of the 10% over-the-fight damage loss from no longer having Berserk.
Yes, we probably get more Fell Cleaves and beast gauge in general from the new IR. This will not make up for the loss in damage from Berserk and SE however, because beast gauge and potency increases aside, we are still losing out on auto attack damage. AA damage accounts for anywhere from 15-20% of our total damage in a fight, so a 10% loss in AA damage is a flat 1.5-2% loss to overall dps. FC raw damage will be down by about 7% total, but some of that (likely not all of it) will be made up with a greater number of Fell Cleaves. Every other non-FC GCD will see a damage loss.
The new Berserk/IR also screws with stat weights. STR on the right side will still be better, but it's relative value is lower compared to when Berserk was a 30% increase in damage. Tying our damage boost to DH and crit stats means to get the most out of IR/Zerk we would need to stack the relevant stats. Well, if we want DPS we already (mostly) stack DH/crit on the left side, and STR reigns supreme on the right. That won't change, but each point of STR now means less because our damage buff is based on crit/DH instead of raw attack power. In short, it's another nerf to toss on the pile.
Finally, some people have noted that you can now use IR in Defiance, and cited this as a reasonable exchange. I disagree; the meta of the game, as SE has built it, is focused around damage. Every single fight of note in SB has an enrage timer, and in some cases multiple DPS checks above and beyond just the rage timer. Whether it's adds in OS3, Shinryu's heart, Susano's rocks, Lakshmi's enrage or [insert any other extreme/savage fight here] there is some kind of dps check/enrage timer in play. Defiance, as a result of the SE nerf, now has even less damage than it did before. This is on top of the absolute loss of damage from Berserk.
Early estimates are showing ~5% dps loss for WAR overall, and I'm inclined to agree with that. But more than that, the "feel" will be changed. The class is no longer about a modicum of planning out your beast gauge usage. You just press button and receive damage. That's boring. It's also less effective than it is now, meaning the "dps" rotation for WAR is no longer about any kind of reward for the planning you do around your gauge. It's the beginning of an invalidation of the entire beast gauge system, and it's patently unfun. Yes, I know I haven't tried the changes myself, but I have played games where a similar mechanic exists, and they are boring. There's no reward for playing well. I like being rewarded for playing well, and knowing that when I screw up there's room for improvement, and the new Inner Release removes any sense of accomplishment from doing things "right."
I can't make any suggestions about what to do in regards to this, cause right now my head is still full of f*ck. But I can say that the SE/Berserk/IR changes altogether make the class worse off than it is now.