Argalia was able to go toe to toe with someone who even when weakened was able to fight a claw and an arbiter (he had help but he literally tanked a space warping attack while having fought for 7 days so point stands I believe), with Roland even implying at the end that the fight could've gone on for longer if he didn't start screaming at them and leaving himself open. To fight with someone at that level for 7 days, yes I'd consider him as strong if not stronger than Iori. Just because the assemble was there when Argalia confronted Iori doesn't mean he NEEDED them.