A few points to make on this topic. First is that species implies incompatibility in terms of romance. In other words, if there is no way for the two to have children, then they would be considered a different species. Cats and dogs are of a different species because they cannot mate and have young.
When D&D first began, the races were compatible. You had elf, dwarf, halfling, and human. Although you did not see half dwarves or half halflings, that is mainly because people did not like the concept of such races intermingling. They didn't mind the concept of elf and human because they were of the same size and were relatively close in many ways.
It has evolved since then to include a lot of other races. Although you don't see half tieflings or half dragonborn, there is still a sort of freedom in the game to build such romances should the players like the idea. Shoot. You now even have half ogres in D&D. I'm not even sure how that works. I don't think I want to know.
But if you tack on the label species, it immediately puts up a mental barrier that says that those two races are incompatible and unnatural. Immediately, one starts to think that if they had a romance between, say, a tiefling and a dragonborn that it would be like a romance between a bird and a fish or a cat and a dog. It starts to get kind of creepy.
As it is, the more creature the race, the more creepy it is for me. A dragonborn romance with any other race but a dragonborn is just kind of weird to me. The same is true for many of the races the further away from human you get.
But anyway, in terms of people treating different races more harshly in the game, they have had people respond to drow differently. But they did not want this to be a hindering part of the game, so right away they have Zevlor say that he is going to announce to everyone that you are a friend and not an enemy so that you can actually interact with people in the Grove.
But lots of characters actually react to you being a Drow. Goblins immediately see you and treat you like you are their Superior. Kagha is very excited to meet an under elf. Minthara makes a comment as well as does Ragzlin.
The point is that they have these things in the game, and I think they do it pretty well to avoid players getting frustrated if they're playing a member of a certain race. They could maybe do a little more with some of the other races like the Gith, but overall I thought they did pretty well.
As for sun sensitivity, I would not want them to put that into the game for your drow character unless they create a day-night cycle. Imagine having disadvantage on all of your attack rolls and skill rolls while on the surface. Just about every fight in the EA you would have disadvantage for. No thank you.
Don't get me wrong, I want them to implement a day night cycle so that they will put in the Sun sensitivity trait as it should be, but if they aren't going to do day night, then absolutely no. That would make them the worst race to play.
