The new Solar is crazy. Basically an at-will Power Word Kill but with 600 feet of range, and its melee attack has a ranged option. Plus it gets Legendary Resistances, which it had none of in the 2014 rules.
That's disgusting that woman has hairy legs! WOTC clearly doesn't want women to be feminine and not have body hair like normal women! (Sarcasm if that wasn't obvious)
You know I saw it but I didn't want to feed the trolls.
But that becomes a problem when some classes rely on short rests for their baseline. Fighters, Monks, and Warlocks are particularly shortchanged if you only take long rests.
I don't like the redesign. I'm okay with making it more monstrous but the way some of the arms appear to be coming out of the stomach instead of the back just bothers me.
I'm not the biggest fan of the new counterspell in theory, though I haven't ever taken it.
I had it used against a character casting a level 4 spell and thought it would have no effect. The DM surprised me by saying we were using the 2024 version which I don't think we'd discussed before. So...
The Marilith has the 'Reactive' trait. It doesn't mean she's nuclear, it means she can take a reaction on every turn in combat.
Usually the marilith uses it to either make OAs or use Riposte, but your monster could use it to hit back.
The point is that no matter how simulationist or gamist you're making it, you're still abstracting things. Different mechanical representations of the same story exist because the above-game function of an NPC statblock usually to exist for a few rounds until the PCs leave or defeat them and it...
Honestly if I were going to redo it, I'd make it a Bonus Action touch range spell, concentration for 1 round and it adds 1d4 to your attack, stacking with Bless etc. Basically an arcane response to that divine spell.
I think of it like this: your NPC Evoker Wizard 'actually' has the same number of spell slots as a 12th level wizard in the fiction but it's mechanically abstracted for the few rounds the wizard participates as a combatant. (An actual 12th level Wizard probably doesn't have 121 hit points, but...