This seems like a very minor thing. Can you play a drow? Yes. So why is it a big deal that they are listed as their own race?
As for the two types of Drow they went with, they did this for story element purposes. Certain dialogues are triggered based on whether you are Llothsworn or Seldarine. It's a video game. Like the druid wild shape choices, they can only allow for so much freedom. The idea is, are you basically a good Drow or evil Drow?
As for religion, only if you are a cleric do you truly pick what god you serve, so whether you are Seldarine or Llothsworn, it makes little difference. Even when given a choice as a Llothsworn to mention Lloth, it is just an option. You can ignore it and choose to even forget Lloth and serve the Absolute or not. It's still all up to you who you serve.
I'd rather have Larian focus on more important things than taking the Drow race and throw it in as a subrace and rework that whole thing when the end result is still going to be roughly the same as what we have now.
