Interesting, but still Lizardfolk are still strange so Larian would be forced to rewrite large portions of dialogue because of their reptile nature, which would still be too much work for such an unpopular race.
In the end, I prefer fewer races but I want to consequences for choosing the race instead of having 20 race that only affect stats and visuals.
This is exactly what Larian is looking for, and Larian likes Lizard races, they have one in Divine Divinity. Also Lizardfolk are mentioned right in the Baldur's Gate Gazette in BG: DiA which Larian Studios helped write with WotC. I don't think that is, an accident.
There are Cyclopses in Baldur's Gate too and I think we can all agree that they won't be playable either...
The Lizardfolk are just boring tribals you cannot compare them with the Lizards and their ancient Empire making them a playable race when they are already Dragonborn(Which are also boring compared to the Lizards) makes no sense. Although they will probably be there as NCPs or generic mobs.
Lizardfolk aren't just boring tribals, they have a complex history in the Forgotten Realms going all the way back to the creator races and a alien mind set.
I have no idea what you see in them, they have a long and proud history of being low-level trash mobs since 1st edition and more recently as hapless tribals threatened by more intelligent humanoids. Out of the Sarrukh related races, it's always been the Yuan-ti which got the most attention.
I would be surprised if we don't meet them both in BG3(hopefully we don't have to fight them like in NWN which I quit because of the railroading).
Though I can say with absolute certainty that Kobolds have a higher chance of becoming a PC race in the future than lizardfolk.