It is still however, tied to Eastern locales in DnD. Which... Baldur's Gate is not. Sure, a PC could be a traveller from the East... But it's still an out of place subclass for the setting of BG3.
Just as Dragonborns are?
Just as Githyanki are?
Dragonborn are somewhat out of place for sure. But they're part of the PHB, which is what BG3 is based on.
Githyanki aren't out of place. Like, have you actually played this game? They're literally the main plotline of the game.
And even if not, just bcs some subclass originate in eastern parts of Forgotten Realms, it dont meean they exists exclusively there and nobody else in whole world is allowed to become one, or invent the same thing on their own.

Yeah, but the thing is that Samurai is very much still based around Eastern parts of the world. With direct references to the Bushido code.
It doesn't make a lot of sense for it being available in a campaign that has no ties to this area of the world.
Yes, you can make exceptions and maybe you can ask your DM to allow it in a TT game, but it's not something that's going to be common enough that it's logical to have it be available to anyone.
Both are focused around becoming large and gaining bonuses for it.
In other words they do one thing simmilarly.
I dunno man, feels like this argument cant stand on its own legs. :-/
They both get big and deal bonus damage and have bonus saves due to it.
The only difference between them (Especially in BG3's limited level cap) is Rune Knight having that Runic Shield feature to reduce the damage an ally take while Giant Barb gets bonus action throw a person.
If doing one thing simmilarly enough is a sign for abandoning one subclass ...
Then why do we have Eldritch Knight and Arcane Trickster? They are not simmilar enough?
And what is this big difference between basicaly all Wizard subclasses?

Not to mention that Elemental Monk is redundant aswell, since all he does is basicaly what wizard do, just worse and more expensive.

The difference here is that these subclasses are all part of the PHB. They're not being chosen as a one time update and being picked from the optional modules.
I'm sure if these were all from extra modules, and Laraian were down to picking and choosing what might be interesting to add in an update they might make some different chocies.
P.s. Ripping on Elemental Monk is asinine, given it's one of the most unique subclasses in the game, since it differs from all other "Gish" like builds in that it doesn't actually cast spells. All its "Spells" are actually "Spell-like abilities" meaning they don't use casting stats, don't use spell slots and are considered attacks. Yes, these "Spell-like abilities" might be similar to regular old Arcane Spells but the class still provides a lot of uniqueness in the differences between them.
Then Shooting Seeking arrow as Arcane Archer, casting Magic Missiles as Eldritch Knight ... or basicaly anyone else, since quite litterally anyone can have this spell ... should be the same aswell, no?

Not really. Seeking Arrow as Arcane Archer is using a ranged weapon to shoot this effect, which is actually nothing like Magic Missiles. 1) It still has a defence roll (Dex save can half the damage) 2) It deals only 1d6 (2d6 at 18th level) damage compared to base Magic Missiles 3x 1d4 3) It is stopped by full cover and 4) It provides extra information about the enemies location (If they fail the dex save)
Then of course Magic Missiles... Isn't a subclass feature. It's a spell.
Except "Range Ranger" is a playstyle choice, not a class one.
What is so "except" about that?

It's not a class feature to be playing "Range Ranger"
Meaning that the class and its subclasses are not in any way similar to the Arcane Archer subclass.
I see little to no difference thematicaly between Arane Archer and Eldritch Knight ...
Sure, they *CAN* be build differently, but as someone said not so long ago that is a playstyle choice, not a class one. :P
Eldritch Knight becomes a 1/3 caster and gains access to spells.
Arcane Archer gains access to unique ranged attacks.
How are they in any way similar?
Yeah wich have nothing to do with the fact that DnD provides like thrice as much meele weapons, than ranged huh? xD
Which is irrelevant. The class and subclass is not directly based around ranged attacks.
Thus Arcane Archer is not similar to them, since it is entirely focused around ranged attacks and is the only subclass in the game that actually does.
Yes, someone can play Ranged Ranger or Ranged Rogue or Ranged Bard and leverage features that can be used in either melee or ranged for ranged attacks. But Arcane Archer is explicitly focused on only ranged attacks.
Which is reflected in all the Githyanki we face in game. Not all of them are Fighters.
I said subclass ...
If you are trying to pull out this "that is not a class" on Ranger ... then stay on it on Fighter subclasses ... be consistent. :P
I don't get what point you're trying to make?
Not all Githyanki are Fighters, meaning that they have a wide range of variance in what an individual's capabilities are.
This can also include Githyanki who ARE Fighters, but don't have strong psychic abilities and so wouldn't be Psi Warriors. Or opted to hone their martial prowess and became Battlemasters or Champions. Or they had some connection to the weave and became Eldritch Knights.
Which is the thing. It's only the "MOST FITTING SUBCLASS" for a Githyanki who; 1) Is adept in martial warfare (Fighter), 2) Is psychicly powerful to leverage their abilities in combat and 3) Chooses to focus on combining these aspects. Which is not necessarily so common as to warrant its inclusion as a subclass (Especially a generic subclass that will be available to anyone. It's much the same thought as Battlerager Barbarian which is by default restricted to only Dwarves)
"Being Cool" isn't enough of a reason to choose various subclasses.
Oh come on ...
Most of the time its the only reason. xD
Not really.
Heck, you even are bringing up the point about "Arcane Archer" being similar to Ranger as a reason why to not include it.
There's plenty of "Cool" subclasses that simply don't work in video game form. Either because of features that just don't do anything (Things like understanding languages is rendered completely moot in video games and especially BG3). Or because features simply don't have any use (For example, I think Fathomless Warlock is cool. But outside its tentacle all its class features are useless in BG3 because you spend literally 0 seconds in any bodies of water)
While some subclasses might have features that are difficult to implement (Or outright impossible given the way the game is set out)
Being "Cool" is one of the main draws to a certain subclass, especially for this update where they're selecting one additional subclass from any modules to add to the game. However, it's not the end-all-be-all factor for their selection.