You know, I can actually see Gouging Fire being a very good Pokemon both for support and offense for later 7 Star physical attackers, especially for ones that are weak to fire. With Burning Bulwark being a Fire version of Spiky Shield that replaces damage with burn you'll no longer have to rely on WoW, not to mention it also gives an easy way to burn through the shield, and that's not even getting into the fact that he gets Breaking Swipe. Sadly he will have to rely on Howl/Dragon Dance to boost Atk, though I suppose having Howl won't be too bad if your allies are physical attackers as well. Not to mention if you fully invest in Atk and give him an Atk nature Temper Flare can deal so much damage under the sun. For reference, this is how much damage it does against a fully Def/HP invested Def nature Arceus while Tera without any boosts besides Protosynthesis.
252+ Atk Protosynthesis Tera Fire Gouging Fire Temper Flare vs. 252 HP / 252+ Def Tera Normal Arceus in Sun: 204-242 (45.9 - 54.5%) -- 5.9% chance to 2HKO after Leftovers recovery
And it may actually be worth adding a filler move like Sleep Talk and intentionally cause it to fail just to double Temper Flare's power because if it deals that much damage with a 75 base power move just imagine 150. Granted that means you'll lose out on recovery with Morning Sun, but I think the health gotten back from Shell Bell will make it worth it.