I haven't played the beta, but if Wrath of the Righteous retained Kingmaker's worst traits (warning: a rant)...:
- the tedious overtuned combat being most of what the game has to offer (apart from perhaps the middle where you can get ahead of the power curve), testing not one's skill but how min-maxed their characters are, something that D&D/Pathfinder handles very poorly what with the spells, resting, and death implementation. The endless Wild Hunt battles in the final two chapters of the game are some of the most obnoxious, time-wasting, luck-based trash fights ever conceived for a CRPG. And while on the subject of being overtuned, having DC 20+ skill checks at the start of the game constantly and hitting as high as 45+ by the end turns it into a savescum fest. Who needs balancing, anyhow? My last 20 or so hours (Pitax and onward) turned for me into an absolute slog that I really wanted to end sooner rather than later, and yet it had the gall to keep going.
- the unbearably verbose and awkward writing that doesn't even manage to maintain consistency on characters (Amiri constantly switching from being very articulate to barely stringing a sentence together), with such a big emphasis on the characters' alignment rather than their actual personality (which, sometimes, is the only part of their personality - see Valerie and how dim-wittedly she behaves to fit into the Lawful Neutral archetype) that it's practically impossible to get attached to anyone, except for, personally, Jubilost (whose character, at least, makes the verbosity and overnarration make sense) and the DLC tiefling twins.
- the plot that is incredibly transparent and obvious but is sloooooowly spoon-fed to the player along with their character who remains clueless for about three times as long as they should have. Really, why would someone named "the guardian of the bloom" be responsible for something literally called "the bloom". Inconceivable! And having your main villain's motivation be "just 'coz, lol" is infuriating, frankly.
- the pointless and shallow RTS mode added on top that has all the depth of your average mobile game and requires about as much thinking, and devolves into an utter unbalanced nightmare at the endgame which is better just skipped by making your kingdom indestructible.
- the practically complete lack of character expression apart from, again, alignment - and romances. I played as a paladin first, now tried again as a wizard/cleric/mystic theurge as WotR draws nearer, and there's hardly anything different based on the class and deity. It doesn't affect your kingdom options (but guess what does - freaking alignment!) or provide any additional choices - at most you either can or can't detect magic, and that's about it.
- the awful quest design and scripting that made me waste a lot of kingdom stats because of the game locking story progress until you do a very specific obscure thing (Brineheart and dealing with Pitax influence).
...then I don't have too much hope for it. Solasta was rather disappointing as well, because it did nothing well apart from the ruleset implementation (and even there they screwed up here and there). All the while BG3 actually offers a highly interactive, reactive, and deep experience that goes beyond just watching your stats grow and optimizing your gear for the next dozen or so hours of endless grindy combat that amounts to always having all your spells active and hoping your rolls outsteamroll the enemies', which really makes me second-guess replaying Kingmaker.
Then again, I loved PoE2, which is apparently seen as some kind of mental deficiency by the more elitist folk out there. So what do I know?
