One of the things I am loving so far is how much the enemy AI has improved and how varied the encounters are

Ghouls charge, robots overheat, deathclaws actually dodge your bullets

Raiders attack smartly. They take cover, they attack from different directions. Even if they don't know exactly where you are they react to your presence by firing in your rough direction etc

The enemy AI makes you think more about your approach than previous games and this time a mistake is as a result more highly punished

I've noticed too. I think that is a big part why the game feels tougher than the previous ones. Very nice that they paid attention to this, and sneakily didn't even mention it before release

Alas, https://www.youtube.com/watch?v=lHbF9ynGZV0

I rather had the impression enemies are dumb as [censored].

I play survival difficulty and had some hilarious encounters with supposedly hard monsters.

Top 3 would be:

Deathclaw in the starting area, after about 50% of the fight it got stuck in the hole it originally came out.

Lucky me I had no ammo for minigun left.

Legendary super mutant skirmisher in Diamond city.

Gets attacked by security at the same time. I go up some stairs next to it, stand 1m away from it, it keeps attacking security down in the street.

Legendary Feral ghoul roamer in the subway station.

It crawls up behind some sign or something, basically sneaking up on me. I was looking that direction, so I shoot at once, get a sneak attack and finish it off with 2 shots.

I also have the feeling the games is harder. It is most likely because of several reasons. One are the missing skill stats. That in combination with ignoring combat perks makes you hit the F9 key quite often. Another is the missing time freeze in VATS.

But i too think the combat a.i. is better. After the damn mongrels near Concorde made me die a few times, i used a small bus as a shooting platform. That worked exceptional well with the 2 normal mongrels. The alpha thou had other ideas. He jumped at the roof and killed me. Second attempt, he didnt jumpd thou, but the bus started to burn. I didnt remember hitting it in my panic driven shooting spree, so i dont know why it started to burn. Didnt matter, as i flew throu the air shortly after. Remember never to quicksave atop a burning bus with an angry alpha mongrel waiting at the ground...