Is this not a question of how complicated you want to make your game?
I always thought of DND AC as a combination of accuracy and effect. High AC might just mean you get hit but it doesn't do anything, or it could mean you dodge everything, or the attacker whiffs, or some other intervention happened. I've seen DMs do similar.
You want it more complicated, home brew some rules to make it more complicated, right?
I for one don't mind mathy/complicated games, but, as you say, fun should reign.
I guess my real question is, "Why Don't Any of the Lite Systems Use Soak?". You already got two rolls, a hit roll and a damage roll. Make the hit roll actually a roll to hit, and have damage that has to exceed a threshold.
But ok, I don't want to sound like an ignoramus. I get it[1]. It changes the game pretty fundamentally, and totally throws levelled systems under a bus.
Dig it: if your soak and "hit points" go up consistently, it's not going to be long before a lot of damage sources are just meaningless. That cuts into the drama of the game, it actually makes it a different genre; worth noting here that Hero started out as Champions . . a superhero game.
Now my counterargument to THAT - and yes, I am arguing with myself, it's Friday - is that some of the boss monsters in the DND5 module I ran for 4th level PCs had over 200 HP. Two Hundred God Damn Hit Points We're Going to Be Here All Night. So, which is more meaningless: doing 11 HP of Magic Missile to a 200 HP behemoth, or doing nothing at all because he's soaking 11 points of damage? Well, by definition the second one. But the first one can get damn boring if the GM lets it turn into a HP counting contest[2].
And a good GM never lets it come to that.
The encounter is never just a flat grid and a monster, it's a lava river, a waterfall, cliffs, flying mounts, a vat of toxic goo, freezing cold, the deaths of friends. There's also a real time component in addition to the game time: at one hour playtime, the players hear a distant army. Two hours, the ork scouts spot them. Three hours, they see the mass of the army. Etc, etc - the point is, the world moves on with or without the PCs, but the path it takes changes with the actions of the players. Gives the players a sense of danger, urgency, and reinforces the suspension of disbelief since the baddies aren't sitting in a cave waiting to be murdered.
[1] And let's be honest, people that want lite games are going to Fate anyway.
[2] Which - if I'm playing - my Bearbarian Druid is going to win, because damn, that build NEVER runs out of hit points.
My DM will often check the bonus the armor offers and, if the attack was close enough to hit that it was blocked by the armor's bonus, describe the attack as being stopped by the armor. Shields (spell and equipment varieties) work similarly. Otherwise it's dodged.
I always thought of DND AC as a combination of accuracy and effect. High AC might just mean you get hit but it doesn't do anything, or it could mean you dodge everything, or the attacker whiffs, or some other intervention happened. I've seen DMs do similar.
You want it more complicated, home brew some rules to make it more complicated, right?
I for one don't mind mathy/complicated games, but, as you say, fun should reign.