For what they're worth, here are my observations about 0.4

* player power is definitely increased for 0.4. Not only is there more power accessible near the starting location of the passive tree, but item progression is also easier: I've never felt starved for gear upgrades when I needed them, and didn't notice any shortages of things like Augments to fix elemental resists, and so on;

* the base attack speed increase for melee attacks is definitely noticeable, and melee combat feels so much better now. This didn't look like a huge change on the patch notes, and I was skeptical about how much of an impact they would have, but I was wrong to ever doubt: quarterstaff skills all feel significantly snappier and more responsive as a result of this tweak;

* with these changes to melee pace and feel, and also the boost to player power overall, act and side bosses are much more manageable. This was a major issue I had with the game (that you could clear everything leading to a boss arena with ease, only for the boss in that arena to be something of a brick wall), but the issue is now resolved -- boss fights are exactly the sort of exciting set pieces that I was hoping for, providing tension and challenge without unnecessary frustration;

** I'm guessing that some folks will be lamenting this increased accessibility of the content, yearning all the while for something more akin to Dark Souls' "git gud" levels of plodding and punishing difficulty, but I was never expecting PoE2 to be Dark Souls levels of punishing, and I'm fine with 0.4's level of difficulty;

* this balance change also impacts the Sekhema Trial, which I was able to down on my first attempt and actually enjoyed this time. I have loathed and dreaded this Trial since PoE2 launched, but if my subsequent attempts at this Trial, or the Chaos Trial, feel this good, I may change my mind about that. I'm still not huge fan of the structure of the Trials, and was hoping see more changes to Trials in this release, but if they're able to dial in the balance of the Trials properly instead.... I might be able to live with them as-is;

* the Vaal Temple is also a bunch of fun. I didn't love either of PoE1's Vaal leagues (Incursion, in particular, may be one of my least-favourite leagues), and I didn't love Synthesis either, finding it overly-complicated, unintuitive, and unrewarding, but the Vaal Temple combines the most interesting ideas from both of those, but keeps it all very intuitive and rewarding enough that I'm enjoying every engagement with it. This is a solid add, and I predict that it will also go Core;

* the modified Abyssal mechanic also feels well dialed-in, and I'm enjoying it again as well;

* overall game performance also feels great. The few hiccups they had early in the league didn't actually affect me at all, and my performance has been butter-smooth the entire time so far, although my hardware has always played nice with PoE2, and I'm nowhere near the madness of the end game yet, so take this observation with a grain of salt, but still... feels good man.