Well... Going from Divinity lore:
The 7 Gods who made mortal races in their image provide the following:
- Eternals (The race of the Gods)
- Humans (Created by Rhalic)
- Dwarves (Created by Duna)
- Elves (Created by Tir-Cendelius)
- Lizards (Created by Zori-Stissa)
- Orcs (Created by Vrogir)
- Imps (Created by Xantezza)
- Wizards (Worshippers of Amadia)
Though, technically "Wizard" isn't a race, they are a group made up of other races that have magical powers as Amadia didn't want to create her own race.
Outside of these races, there is note of others within existing games:
- Dragons (And Dragon-Elves)
- Goblins
- Trolls
- Halflings
- Ranaar (Weird blue aliens from another planet)
So far, we see most of the main races represented in DOS2 and the current trailer (Which depicts Orcs). With only Imps not being very prominent given the discrimination against them and their ties to Demons.
Dragons, Trolls and Ranaar are unlikely to be playable races for obvious reasons. Dragons are ridiculously OP and also pretty sizable. Trolls are massive too (And ridiculously stupid). Ranaar don't make sense in most Rivellon based stories.
Goblins and Halflings could be a thing. Though Goblins tend to be used as low level enemy fodder more so than a proper race to be accepted by main factions (And while yes, they did let you play as an Eternal in DOS2 it was under the context of you supposed to use the Faceripper or a hood to hide your face so as to not be attacked). Halflings would require a lot of work to write into the lore, they've been mentioned to exist but there has been otherwise no information about them and having them suddenly pop up and no-one batting an eye would be jarring.
Dragon-elves could maybe be a thing too. Though again it would be reliant on writing them into the lore sufficiently to make sense.
Ias well as 1/2 varients of all plus orcs.
Ugh... Please no.
At this point I'm tired of half-races. Especially when it's always "Half-human" and often meaning we get some crappy humanized version of a race instead of the actual unique race with their unique culture and physiology.
It also doesn't make much sense biologically. Literally, these races are created from compltely unique origins. There's absolutely 0 reason why cross-breeding would exist.
Otherwise, if there is no difference why have different races at all (other than origin stories which of course is a good reason if only relying on that).
Appearances?
Dialogue options?
NPC interactions?
There's a lot more to racial diversity than shoehorning in statistical differences that only really serve to limit creativity by pushing certain builds onto certain races.
So say nothing about having fixed statistical differences makes a mockery of the very nature of individuality. Literally in real life, humans aren't just one single statistical group. You get some people who are smarter, some people who are more charismatic, some people who are stronger etc.
The very nature of diversity means that you will get variations. Which would preclude all races having equal stats, then you as a player decide how to distribute things based on your specific character. Meaning you're not stuck because you wanted to make an Elf who was naturally hardier than most other elves but less agile because some random designer decided that literally no elf can ever be anything but frail and agile...
Please at least have 5 characters instead of 4. It will allow you to have a custom character + enjoy the banter and origin stories of 4 characters in your party.
With that logic, why not a party of 6 so you can have 5 origin stories? Why not 100 so you can have 99 origin stories?
Personally, I'd err towards a lower limit. Like 3-4. As it opens up more balance oportunities for more options. Whereby going solo is more feasible or only taking 1 companion.
The higher the upper limit, the more the game balance revolves around having this large party and the less of an option it is to go with just 1-2 companions you really like - At least, without game warpingly OP perks like DOS2's Lone Wolf.
Also, a lower limit means more replayability. Since instead of just taking all however many Origin companions along with you all the time, you instead are limited so you have to play through multiple runs to see all their stories play out.
I'm generally not a big fan of the whole Pokemon-esk "Gotta Catch 'em All" approach to companions, where you just bring everyone along all the time, so that everyone has their impact watered down because they're only a fraction of the party.
I'd much rather have fewer party members, but each person has more impact on the game and story. More unique interactions with NPC's, more scenes where they take the spotlight, more specific inter-personal relations (Not just a few lines of banter here and there, but actual interactions like scenes where companions interact with each other, changes in how companions interact over time, effects of decisions they make in how other companions see them etc.)
Also allows you to have one different character that brings unique but less used skills because if you only have 4 most people will simply train up Tank, Ranged, Magic, Rogue. We might with 5 have some wiggle room to have non standard builds that add flavor.
I mean... That depends a whole lot on how the mechanics will play out.
DOS2 had a more freeform approach to roles. Mostly due to the shallowness of individual skill lines... Like even if you went "Tank" or "Ranged" or "Rogue" you'd max out your Warfare/Huntsman/Scoundrel lines pretty quickly and would end up picking up some magic skills for support (As well as access some split skill abilities)
To say nothing about how in BG3 the concept of "Roles" is largely irrelevant. Any party can function just fine. You don't need a "Tank" or a "Ranged" or a "Magic" or a "Rogue" and you'll rarely ever even notice if you lack any of them (Really the only thing I can recall off the top of my head is the Avatar of Myrkul fight, where having a tank to sit on the platform and get attacked by the bosses melee attacks can be preferable to him spamming his ranged AoE skills)
If combat isn't designed around having a specific set-up then there's no pressure on players to build for it outside them WANTING to do that.