I think this reviewer has some useful insights. He work on the original Baldur's Gate. It's a lengthy read, but may help if you are on the fence about early access.
By Steam user: Zakuen
Full disclosure, I worked on the original Baldur's Gate series as a designer with a focus on scripting. I also was hands on with a bunch of areas (putting quests into play, setting up 'cinematics', creating items and monsters and so on). I'm honestly not sure how to approach reviewing Baldur's Gate 3 in early access. I've worked on many games over the years and been in many early access and beta tests. So I'll do my best to approach it with this mindset, but I feel like I've been in enough early access or betas to realize how some things probably won't change too much from how they are now. But as someone who worked on the originals, I felt the need to comment I suppose.
Who Am I: A scriptor and designer that worked on Baldur's Gate: Tales of the Sword Coast through Baldur's Gate: Throne of Bhaal, also spending some time with Neverwinter Nights.
(Designer Mindset): I'm going to list my opinion from a designer standpoint instead of a gamer afterwards essentially. If you announce something as Baldur's Gate 3, I have certain expectations, I'm sorry. Otherwise, Baldur's Gate: Illithid Invasions or Whatever Name would have been preferred, or even their own Forgotten Realms IP. But the choice to include 3 means something to me so I'll be treating it as such.
Initial Impressions: It feels like an updated new Divinity Game, but using the ruleset of D&D 5E. It's not a BAD thing, but it doesn't feel very 'Baldur's Gate' like to me. Pathfinder: Kingmaker and Pillars of Eternity feel more similar to what I'd expect from gameplay, or at least more of a mix somewhere in between would have been welcome.
(Designer Mindset): I feel like some of the big keys to Baldur's Gate were unspoken but always there, including trying to include a great story, memorable characters and quests, many choices in how you portray your character and approach things, and a mix of real-time D&D combat. So far the lack of a real-time combat component personally has me thrown off the most from feeling like this is supposed to be a sequel of any kind.
Character Creation: Early access allows 6 classes so far, out of potentially 12? With the lower levels of D&D it feels like many skills aren't available yet, and most of the lower level skills are a bit more simple. So it has me wondering if the hold up on including more classes is on purpose, or is something else going on? I love the options from backgrounds to classes and races, as it's clear at the end of it all they're trying to include as much as they can. Face and Hair options currently have me wanting more though. Faces feel very similar to each other with some of the races, and the hair options while quite a few, I found it difficult to find one I liked. Almost as if there was TOO much flair and curls added, when all I wanted to find was a simple hair cut.
(Designer Mindset): As a designer, I remember making many battles focusing on different classes and subclasses within the enemy encounters when I was able. We'd use their abilities to script fights and let the rolls and tactics figure it out for the most part. So I feel like if only 6 classes are included so far, then the same is said of all npc's and encounters in the game. Which in turn, then has me wondering how this will change along the way, if at all? Not saying it won't, but it feels strange to me personally that more focus wasn't put in completing more classes to some degree first.
Gameplay: It feels like Divinity, but switching in D&D 5E Stats, Abilities, Skills and monsters and so on. Again, it's not a BAD thing at all, and it's enjoyable, but it feels like I'm playing a new Divinity Game set in Forgotten Realms more than anything.
(Designer Mindset): This one is still difficult for me as I feel more like I'm playing a new Divinity game more than anything.
Which again I DO enjoy, but it's not what I'd expected from a game labeled as a sequel. It feels too different, and while I expect changes over the MANY years and editions of D&D since then, it doesn't feel quite right regardless.
Companions: So far there are 5 companions available, most likely one of which you will NEVER use, as party size is limited and you won't want to double up with your own protagonist's choice in class. I haven't played far enough to be fair, but initial impressions are there is a lot of anger and bossy people in this world, and not enough fun and adventure seeker's.
(Designer Mindset): Pathfinder: Kingmaker I feel did this wonderfully, as you had someone cheerful available near the start, along with someone barbaric, some morally questionable choices, some valorous choices and so on. So far it feels as though everyone is out for themselves, and it's a bit hard to like them a whole lot as a result.
I know this CAN change, but going off what I feel so far is that they aren't memorable due to their personalities, but to something afflicting them if anything or a personal goal. That is more memorable than any type of personality so far. I don't know that this number of companions will change a whole lot either, which is unfortunate as I feel like a big part of what made things memorable for BG before was the choices between many companions and party make ups.
Why Baldur's Gate(?): I feel like this is the big question so far, and while I'm sure they want to maintain some mystery, but I guess I don't understand the choice yet. The game play while enjoyable feels too different from what I'd expect given the BG3 title. The change in party size, the way the turn based combat works, it feels too different. I'm enjoying myself, but it does leave me questioning why go the route of a sequel title then?
Larian has already made some amazing popular games, and if they wanted to go down their own Forgotten Realms story I think it's great, and I look forward to it. But why not a new title? The old designer in me is frustrated that it's named as a sequel, without any real continuation showing so far. Whether it's in story, gameplay, characters or anything. It might be there at some point, I don't know, but at this time, I haven't seen it.
When we went from Baldur's Gate to Baldur's Gate 2, there was an emphasis on growing and expanding on what we could to give the player more choices and freedom. Adding subclasses, focusing on player choices in quests and the story, their companions and so on. There's not near enough choice in companions so far for me to be able to tell them to go to hell if I don't like them.
Verdict: From a game standpoint or a Baldur's Gate sequel stand point? While the story is interesting to me and I'm excited to see where it goes, it doesn't feel like it needed to be listed as a sequel. I feel I'd have enjoyed it more as a surprise down the road if it was tied in without announcing it as a sequel and putting certain expectations in place. The game play is great given Divinity's history, and while I expected the similarities, I think I was also expecting more changes rather than mostly the Stats and Naming conventions it feels like.
There are some bugs, and the game does need polish but its still very playable and enjoyable in Early Access. If you want a full feature and enjoyable game, and you're unable to look past the fact that its Early Access, I'd say try to wait though. I know when its finished it will be an enjoyable and well received game. Even in early access I feel I can recommend it. However, I struggle to feel as though it's any type of sequel to Baldur's Gate so far other than in name and knowing the city itself will make an appearance down the road. One day it might, but not today..
