They have a religion, they decide to switch to that of the Absolute, they have a quasi structured society with gerarchies, they are able to speak and make speeches, they now about pasions and vices.
They've shown appreciation for art and curiosity for books.
To define them Goblin not sentient seems a bit excessive (in the game itself we see the difference with Gnolls, when the tadpole makes itself heard Goblins react with emotions, words and so on, while the only thing the tadpole can sense from gnolls is feral insticts and hunger).
Well I get that you have "talk with animals", but again their phrases are short and really tied to insticts.
Furthermore as other comments stated now we have Drow (elves that pursue an evil deity) and Thieflings (that are litterally the spawn of the devil) and one of the companions is a Vampire, so to use the Goblins aggressive background seems a bit too farfetched.
