You are the one who is misinformed sir. 1.) Stamina Aside my main point that there is hardly any defense difference between ironbone and steel stands correct it's just a few points. 2.) Steel vs Tungsteel once again is only a few points difference as evidence from the video i linked. 3.) I know about Oghmium being good in Mo1 especially with Pierce defense and Draconigena Armatus so i am not sure what you meant about that last part.
You seem to have missed the point of that video.
If you actually listen to what Speznat/Wolfzeit is saying, he explains how what seems like a small difference is actually very significant.
We know through experience that the difference between steel and tungsteel is quite substantial.
Although I agree that metal armors are in a rough place right now because the stamina penalty is arguably too severe, the fact that people aren't wearing them on mass doesn't actually mean they arent good. People might simply choose to wear ironbone armor most of the time because they don't have a large reserve of steel to replace sets when they die, and are saving them for significant events.
Metal armors such as steel, tungsteel, cronite and oghmium saw the most prevalent use during large siege fights in MO1, even though most people would not want to wear it while solo roaming or similar.
There is also something to be said about player skill in regard to stamina management, and playing the exact same way while wearing steel as you would in a lighter material will of course result in you running out of stamina a lot more often with the current systems. I've talked about this in here before, but a lot of people that I see in their PvP videos have quite bad stamina management.
It really boils down to how much you needlessly move around, and how you behave when you do get low on stamina.
1. You will regenerate stamina at a much faster rate when standing completely still, so try not to walk around for no reason while you're fighting.
2. If you do get low, stand still and take a breather by just parrying your opponent instead of continuing to try and fight them while constantly running out of stamina. (Not so applicable when in a group fight)
Do the above, and you'll feel the penalty of metals a lot less, however this applies to fighting in light armor as well and is just more efficient.