For what it’s worth, where are IH now in terms of power level? Is it “safe” to drop them on the table in casual games nowadays, or are they still just too damn strong against your average list/army, whatever that might be?
Hey Brother, I didn't properly address your central question, but I think you're strong with your list (it's a nice, well-rounded, take-all-comers list), not too damn strong. And I think I do understand your key concern (as I play Nurgle for a similar reason).
Players know the nature of 40k, losing is part of the game, but they still want a fight. Pre-nerf Iron Hands wasn't really a fight, it was just weathering a constant storm due to how there was an obvious "strategy" with the ongoing IH uber-Devastator Doctrine: declare your clearly Ultramarines as an Iron Hands successor (I want to call them "Uron Hands" but it sounds like something else), everything has a Heavy weapon, including those Intercessors that are carrying counts-as Stalker Pattern bolt rifles. From an opponent's perspective, there was no like "I'll just hunker down for the 1st turn, then I'll counter-attack, it's tough but I got a chance," because, like stairs, the IH uber-Devastator Doctrine just kept happening pre-nerf.
Now opponents feel like they got that chance. Iron Hands can still raise the storm, and it still hurts, but it does blow over. It feels like a proper fight.
I'll give a great example because I mentioned 1 of my 2 real close tourney-topping friends is Iron Hands, the other is Raven Guard. He's still dominant, but it relies a lot on infiltrating a unit of Centurion Devastators, that's his touch-of-death. He's also a great painter and he actually "true-scales" his Centurions, I should get him to post his conversions here, they look awesome. But an opponent feels he can counter or plan to avoid them. It's a tricky puzzle, but it's one people want to solve. It's a very different feel.
And I'll give you an example for your list, Brother Juggernut! You're taking Hellblasters, good unit! Pre-nerf, Iron Hands players didn't even bother to, because an Intercessor with a Stalker Pattern Bolter Rifle was effectively the same with the uber-Devastator Doctrine. Not only does it remove the idea of choice for an opponent, it kinda removes it also for the Iron Hands player, kinda? Well, Hellblasters are certainly relevant for Iron Hands again post-Turn 1. But pre-nerf, when playing something is that level of no-brainer, then there's really not any playing.
I reckon the broader theme is what professional game devs call player "agency", like their choices matter. Even aside from this, I think GW and even FW sometimes went overboard for certain armies/units/Formations (remember that time?) I think Iron Hands were merely brought to the level of where choices matter, for you and your opponents. It's good.