Psuedo-casual because I take long breaks (obviously) and when I am playing it's usually only an hour or two a night. The last league I went through was 3.15 where I took a duelist through most of the atlas content. Why I don't consider myself a 'normal' casual player is because I used to be quite good at gaming (competitive ut99/guild wars scene) and feel like I can put together pretty decent PoE builds myself. I've never used a build guide.
I have a little bit of time to play and I'm working toward getting my old closed beta character to level 100 (currently 90). Things have changed in the two years I've been away, some for the good, some considerably worse.
The good:
My templar's build is very defensive--maxed out resists including chaos, 75% phys and spell block, lots of blinding going on, high armor, a bunch of renewable minion fodder. Offensively he's using SST with bleed stacking. He's got 42k tooltip dps and melts packs quickly. I hit about 120 million exp/hr going through delves.
Defense actually seems to work now. I've only been one-shotted a few times since coming back, which are my only deaths cause my guy's unstoppable otherwise since his life steal keeps him at full health practically non-stop.
I was impressed with the changes to the passive skill tree. There have a been a lot of nice additions made which look like they would support a lot more build diversity.
The continued time and effort put into endgame variety is noticeable.
I don't know if netcode has improved from 3.15 to now, but from back when lockstep first became a thing, OMG, so much better. I'm actually playing overnight at work via a mobile phone tether and it's doing fine. Good job on finally getting the netcode right.
Edit: Oh yeah, loot allocation seems to have gotten waaay more generous. I had two exalted drop in the course of about six hours the other day and I'm getting six socket items dropping left and right. Also map drop rates aren't problematic, so that's a very good change.
The bad:
I'm a little miffed that the unique map stash tab went away. I feel like something I paid for was taken away.
The absolutely terrible:
WTF has happened with rare mob health? Why do some gold randos have more health than map bosses? Why do I have to use an unset ring with frost bomb just to kill mobs with health regen? This is awful.
So, my first impulse once I figured out some mobs with really high health and health regen were basically immortal for my type of build was just to ignore them and go about my business. However, I'm playing mostly delve for quick exp and decent loot and some of the encounter bosses have the health regen mod so I couldn't complete the delve objective. They didn't stand a chance of killing me either, but my only option was to log out since you can't map out in-game until the objective is completed. Lame. Mega-lame, in fact.
Another byproduct of rando gold mobs having 300 trillion health is that your flask of corrupted blood immunity doesn't last anywhere near long enough for you to finish killing the mob before it's corrupted blood will wreck you. Corrupted blood has always been obnoxious, now it's just game breaking. So there are two things you have to devote skill points/gem slots for on the vast majority of solo builds and it's stupid.
I'm guessing the unbelievable amount of health some rares have is GGG's ham-fisted effort to try to acclimatize players to Chris's vision of a slower play style for PoE 2 but that ship sailed a long time ago. It's stupid and it needs to go away. I don't want to spend five minutes to kill a rare mob after having melted it's pack in 3 seconds.
I also could not kill the Oak boss in Fungal Hollow due to his life regen outpacing the damage I could do to him. This was even with constant spamming of Frost Bomb. Ugh.
Insurance would totally try to claim Act of God on that one.