Except Logan was visibly aging/getting weaker and SS getting younger as the healing factor was being drained. At the point the fight was interrupted, Logan was clawless and totally at the Samurai's mercy. So a more likely outcome is that SS would have drained Logan until death if Mariko had not intervened.
It was mentioned in the film that the vast majority of the crappy suits in IM3 were prototypes Tony built while suffering from insomnia and dealing with PTSD from the Avengers New York battle. So they weren't the tried and tested combat suits he usually sports.
Fact is, based on actual screen feats, Tony's armour has superior showings to SS's armour, regardless of whether it supposedly is Adamantium or not. There is no way in hell, based off of feats, that Logan could just rip panels off of Tony's armour with his bare hands. If SS's suit really was adamantium, all it shows is that Tony's armour is superior to movie X-verse adamantium.