I mean, I'm glad I'm not playing AL; it must be stressful to have your stuff make sense one day and when you show up to the next game, your character background and mechanics have changed.
But there's thing: are Drows now unaffected by Ressurection spells? If so, that a big mechanical effect that may ruin a character.
They haven't said that straight out, but its a logical conclusion. If a Drow's soul dies when its body dies how can you call the soul back from the afterlife? You can't call a soul back to a body if said soul doesn't exist anymore.
Actually it could even be a problem for other elves because if they get reincarnated right away after dead, you can't call a soul back if its incarnated in another living body.
Also what fiend would ever make a pact with an Elf if its soul wouldn't survive its death? I've barely scratched the surface of why this the worst idea they've had in 5e.
I mean its not completely bad for Shadar Kai because it gives then an easy way to united the 3e, 4e, and 5e Shadar Kai, although there still needs to be a period of afterlife before reincarnation, but for other elves its a bad idea, and soul death for Drow especially for those that don't worship the Seldarine, wrecks the entire Drow Society, why worship Lolth and the other members of the Dark Seldarine if it means oblvion, all an regular elf needs to do is prove only the Seldarine can save your soul, and Drow society collapses.
And in FR all souls (that don't gey stolen like by demons first), go to Kelemvour, who judges them and sends them to their afterlife. In FR Arvandor has always been the afterlife for Elves, now they are what barred from it?
All this runs head long into countless FR novels and RPG materials including 5e's own SCAG!!!
What a cluster****.
Runner up for bad ideas is Shadar Kai looking old in the Shadowfell, which btw also hasn't been a thing in the novels.
Least anyone call me a hater, I like that they fleshed out and united the Seldarine, Dark Seldarine, Dwarf, Gnome, and Halfling Pantheons.
Like they added members of the Seldarine mentioned in various products and settings to the regular members, given the Sundering it makes sense too from an FR and Greyhawk perpective. It also paints an interesting picture of the Seldarine.
Like several of these new to 5e Gods function simularly to Azuth, Selvras, and Velsharoon do for Mystria, only for Corellon who is the elf God of magic. One is a God of Enchantment and Divination magic, another is a God of Conjuration and Runic Magic, another is a God of Abjuration and Mythals for example.
Another is a LG Goddess whose the Daughter of Lolth, but who wasn't invovled in Lolth's betrayal, unlike her Bother and Sister and so remained a member of the Seldarine, not the Dark Seldarine but is still effectively a Drow Goddess.
Two of these Gods didn't start out as members of the Seldarine, one left the Fey Pantheon (a Goddess of Nixies and Water) and the other started out as a Goddess of Humans, than was adapted by Elves and Half Elves when her Yuirwood Pantheon was absorbed by the Seldarine).
Each of these Gods when you learn their backgrounds add depth to the Seldarine and Elves.
This is true of the other racial Gods as well.