I would really love to have monk in game and the ability to play with multiclassing before launch.
Indeed ...
Aswell as rolled stats, custom party without multiplayer nonsence, crafting, mercenaries, and many, many, many spells (and other class features) of level 1 and 2 that are still missing ... and those are just things from top of my head that was (at least semi) confirmed.
But we were given a playground where theese things were not ...
All we can do now, is hope that testers in Larian offices will do good job and things will be as polished as possible.
(
But i wouldnt recomend hold our breath ... i dont really remember any game in past decade that was released in top shape ... would be nice if BG-3 would break this whell of missfortune tho.)
Would also love it if they added some of the newer races and sub races
Indeed ...
Sadly, not gonna happen ... Sven himself in one old PFH specificaly stated that they want to keep races as surprise for final release ... and if *certain someone* (
as again Sven himself admited in different PFH ... unless you think it was a joke) wouldnt spoil their presence during a presentation, we probably wouldnt even get Gnomes in EA.

why not the other gith like githzerai
I think i know the answer for this one ...
Its matter of reactions.
Githyanki seems to play cruicial role in story of this game ... Githzerai would need lots of specific dialogues.
Also, if we take under concideration how cruicial role Origin Companions play in Larian games ... i guess it would be quite problematic if one of our followers would automaticly attack us.

But maybe they surprise us!
Same reason as abowe ...
+ Remodeling everything on Goblins would be lots of work. :-/
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The only thing we know is that PHB material is likely to be added.
Indeed.
Anything other than that is very unlikely.
This on the other hand, is just a speculation. :-/