in tabletop D&D when compared to the pact of the fiend the great old one warlock falls woefully short, thought shield and entropic ward are painfully bad abilities and just a glance at the extended spell list will show you that at 5th level one get fireball and stinking cloud and the other gets clairvoyance and sending.
on the tabletop this means that great old ones are better in out of combat situations like translating using awoken mind or using illusions to trick NPCs but in Baldur's gate three the great old ones are just a bad subclass that exists to trap new players into a weaker character.
the player is actively punished for choosing this class. Fireball is one of the best spells in the games and the old ones just do not have anything close to that powerful.
to summarize. great old ones were made for the tabletop and cannot be simply copied into Baldur's gate. their abilities are made specifically for situations that just do not come up in the game like sending or clairvoyance which just straight up don’t exist in Baldur's gate.
My hope is that great old ones warlock just becomes a reskin of the fiend especially because Wyll just outshines the old ones protagonist every encounter.
