Deity might matter, as we have dialogue options with Lolth, I guess these are connected strictly with le evil drow but there are (and will be ) Lolth creatures that obvious can be reasoned...by directly speaking with Lolth or mentioning her. As is in game.
Same goes for Warlock Patrons - they will make their presence known.
Shadowheart obviously is of Shar-Selune thing.
Gale has his thing with Mystra,
Froggie goes full Vlaakith (and we know there will be a n interaction there).
Absolute will probably concern at leasy some gods. Same goes for Dark Urge.
Flavour is the most basic case of "let there be a few lines of dialogue and few lines of code!" but quite obvious decisions can be made with deities practically - as demonstrated above.
I'm not speaking 40 gods, but at least the major ones (there are not many) and about a few special guys - like Lolth(can be worshipped by non-drow), said Vlaakith(exclusively for Githyanki).
Let's say your Githyanki guy worships Selune. Suddenly you have Vlaakith on your toes at some point - like she sends a patrol of Gith to hunt you down (and you have a wonderous occasion to get a silver sword AND after taking it - another patrol of Gith looking for it! Endless githyanki mooks!).
And so on, and so forth.
