New? Not much really. As someone who’s been waiting for the better part of a decade and played countless mods; I’m loving it. It’s essentially the modern stalker a lot of mods have been bridging the gap for. As you’ve said, they’ve largely iterated on what is already a successful game design, so no really revolutionary changes.
There are new anomalies, factions and newish mutants. However if you’re hoping for wildly newer things I don’t think you’ll find it. The typical mechanic are more polished, gun/gear wear, inventory management, PDA (anomaly’s 3D PDA was huge; stalker 2 is better), emissions (although someone need to mod GAMMAs sirens in). Despite the performance issues, which aren’t as frequent for me as others; it is a beautiful game. The lightening strikes, weather and just environment in general. X-ray (especially modded) was awesome but man, unreal is looking pretty.
I feel like the loot tables are better. Unlike modded stalker where practically everyone is rocking a gun that is essentially broken when you loot it off them. Slightly more variety weapon and armour wise. Modding weapons is better imo. Gamma for example, maintaining and modding guns was a PITA (which made sense in the setting but still). Way less fucking around and arguably slightly less depth as a result.
It still needs work imo. The obvious one is A life. It’s kinda fucked atm (which the devs have acknowledged. Even on veteran the human AI feels kinda easy at times. Shotguns need a boost for mutant damage (thought the patch addressed some of the health pools for enemies). Idk give it a go when you can; if you’re not satisfied refund it and try again later. I’ll probably amend this later but I’m about to pass out so it’ll do for now.