If you're putting this on the hypothetical character, then both characters wouldn't walk up to the volcano edge ... I'm not seeing the value of your hyperbole.
There's no hyperbole here. Are you really suggesting that characters should never find themselves in a save or die situation? At high levels would you ever let an NPC spellcaster have access to PowerWord Kill (no save)? Plenty of things can kill characters, and surprisingly often they have only themselves to blame. I don't coddle my players. I don't go out of my way to kill their characters either, but I do expect them to act intelligently with a reasonable facsimile of belief in the world around their character. Acting rashly or without thought will get your character very dead very quickly in my games.
It certainly sounds like it.
But it is as good as light and heavy armor at levels 1 through 7; why's that have to change? And things should be balanced where they can be so that they remain options. (Nice video game jab ...) And we already have stats for inferior armor (leather, hide, ring); why does a whole category of armor have to be inferior?
It doesn't have to change if you don't want it to, but it isn't wrong to stay the way it is either. As I said, not everything has to balance. That guy in full plate is going to wish he had on something else when he falls into a lake and sinks like a rock. Given the don and doff times in the PHB, it's going to be interesting to see what he does (5 full minutes to remove armor, during which he is sinking quickly). Do your characters travel by ship? Smart characters should probably remove their armor when aboard a ship in a bad storm...
How many DM's even take donning and doffing armor into account when characters are resting? No, you cannot have restful sleep in full armor in my games.
Unless those have multiple chances to avoid it, I'd never have them in my game. So we have a different style.
Yes, we have a different style. I think guaranteeing a second chance takes the teeth out of situations that really should be lethal. Not fearing failure (because the DM will always let you have another chance) breaks suspension of disbelief.
I won't resort to personal attacks.
That's good to know. I'm not attacking you.
Could you give me an argument as to why Medium Armor should be even with Light and Heavy up until a certain point, and from then on be a -1 AC penalty for no reward? At least medium armor had lower armor check penalties in 3E; I'd even accept that to a degree (I already accept that having a stealth penalty gives you +1 AC).
I covered that. It doesn't need a reason because there's nothing wrong with it being different. It's just not as good with respect to AC.
Edit: Besides, save or dies can just as likely be Con or Will; and in the case of cliffs, they could even be strength. Sounds like equivalencies to me.
Saves come in all forms and yes they can be against any ability. My point was that all stats are useful in myriad ways in games which include more than just lining enemies up on opposite sides of a grid and rolling dice. Just because that full plate tin-can renders a character's DEX moot for AC doesn't mean the character is necessarily smart to put all his points somewhere else.