When you say mid, or others giving various 7/10 ratings, etc. what exactly are you comparing it to? PoE, Grim dawn, Last epoch, lost ark, etc? or, games in general? or d2 and 3 specifically? or, some theoretical arpg that should exist?
From a standpoint of looking at it from the outside (I haven't picked up the game yet), every video I see screams D3 to me.
Every build I have seen played so far is the same (but slightly different for reach class I suppose) combination of a few things:
-Apply vulnerable. This seems like an absolutely key thing to do.
-Group mobs and blow them up.
-Either have extreme mobility to avoid hits that will CC you or have a combination of abilities making you immune to said CC, or you're basically CC'ed for seconds leading to death. the second part will most likely see nerfs to uptime (already has)
I have yet to see builds that kill mobs from ranged purely. Think back to amazons, or ice sorcs in D2, or many many builds in POE that do that very well, they do not seem to exist here, or are very rare. It really seem to boil down to builder/spender/group mobs/blow them up and dash to the next pack. Every time. I find that just by looking at it that way the build variety seems very very VERY limited, and I think if they are going to introduce sets (they will) it will only reinforce that, but also limit itemization even further because everyone will now play with the same sets since chances are they are going to multiply your damage by 100000 like they did in D3.
Now I'm making assumptions here with how the sets will work, and if I would actually LOVE to be wrong, but the track record so far is there to point in that direction.
This might be a nitpick here also but I find the mobs themselves to be boring and uninspired. Goat men, spiders, fallen, beasts etc are almost straight up copied from D3 with a new look but not quite new enough to make them interesting. I feel there are very little variety in mob type and nothing that is....memorable? If that makes sense? Density also seems to be off for an AARPG. Lot of areas are just empty and you're just running for .....minutes? without really anything to kill. Why?
Boss fights seem to be overwhelmingly disappointing as well according to most players. Nothing in the boss fights seems challenging/interesting. Most people will struggle getting on shot by some weird affix combination, sometimes from a few screen away. White mobs seem way more dangerous than bosses for the most part.
I've never been a huge POE fanboy, I played may be 4 leagues in a row a few years back, and kind of shelved it, mostly because I had other shit to do, however, the variety in every aspect in POE is just leagues above anything D4 has to offer. Yes it just released, yes it looks like a good skeletion for a potentially good game, but they need to put a LOT of work into this, not just tack on a couple of seasonal items on it every few months and call it a day. Will they do that? Does blizzard actually have it in them to do that? Time will tell.
Trading is a sticky point as well, trade only matters if uniques / items have enough variety to really matter.
If combinations of uniques allow for specific crazy combos that open up new builds and new ways to play, then trading takes on a whole new meaning. It seems like the way drops work and the way itemization is already headed in D4 trading doesn't even matter. What currency would you trade with anyway? Gems? these hardly matter? Gold? May be, but that's pretty bland as well. Trading unique for other rare/uniques, but with so few items actually mattering or opening up new build path there's really no point in D4.
One thing D4 seems to have done really well is group play, from pretty much everyone that has grouped it's a pretty clear good feedback there, and it kind of helps justifying the scaling. But scaling is also an horrendous system if you're a pure solo player, and a lot of people play AARPGs solo.
