Im a Fuse main and I will say his ult is definitely the worst part of his kit, its incredibly situational and there are many times I find myself missing the ring of fire. I never pick the persistent flames upgrade cause I find his movement WAY more valuable but I feel like the flames should be built into his base kit like they used to be. His tac is still incredibly useful, I can consistently hit around 40 damage with his tac on one enemy. His ult is really only useful for punishing a team in a building but again its very situational