I started a new game and the zone does feel noticeably more alive and fluid. I've already seen multiple instances of groups attacking groups and/or being attacked by mutants. So this augers well for a-life.
I never encountered any significant bugs, so can't comment as to these improvements, but the change log lists a myriad of fixes. They have improved the iconography for ammo, to clearly indicate type, eg armor piercing.
Other niggles remain. The day:night ratio feels unbalanced and loot stashes are still (generally) worthless - for which I've loaded a mod that helps a bit. I'd rather that there were far fewer stashes, but that they continued on average much better stuff, including the occasional artefact. YMMV
I can't comment to the bullet-sponge mutants as I have this modded, nor to mutant looting as I can't get it to work.
Overall the FPS performance has been fine for me for a while, and seems better again with this release. Similarly pop-in of scenery, NPCs and mutants is gone/much less noticeable.
All in all, a very decent update IMHO. I've given the game enough of a rest that this restart feels fresh, and I'm enjoying simply plodding around and doing the odd main-game mission as and when I fancy.
Cheeki breeki STALKER!