Not really.
On a d12, the most extreme possible example, it averages a little under +2 damage on one
hit (which would be smaller as a value of DPR).
And that's on a d12, so only Greataxes.
On a d10 it's close to +1.6 damage on one hit. d8, 1.3, and so on.
You can use Anydice to check this if you want to disagree. Once you get multiple attacks, it becomes a smaller proportion of your damage. Also note it only applies
now to the Attack Action, not to Opportunity Attacks, Bonus Action Attacks, etc. etc. - So like if you missed with your mainhand or the main attack of your polearm (with PAM), it cannot apply to your offhand. This is a nerf from the previous performance.
For a Great Axe Barbarian focused solely on damage, who is level 1-4, it's not a completely terrible choice, though I'd say it's objectively inferior to almost all the other choices in terms of overall impact on the game. Anyone else? It's pretty bad, and notably, it gets less and less important, whereas a lot of the Feats retain utility.
Feel-wise it'll be a mixed bag, because you're going to see an awful lot of "I rolled middle or less on both dice...

".