A lot of deities disappeared during the Second Sundering or became aspects of other deities. Vhaeraun for instance became a servant power to Lolth, abandoning his former rebellious aspect. So it doesnt make much sense for him to be included.
Didn't know that, thank you. I am still a little foggy on most of the post-Spellplague lore, having spent most of my time with 3e/3.5e. I do know of the Lathander-Amaunator-Lathander shuffle, about Bhaal coming back, Mystra dying (again) and somebody restoring her / claiming her portfolio (again), but I am definitely in need of some educational reading to catch up in many aspects. Like how I am still iffy on how the succubi/incubi are no longer considered tanar'ri anymore, or what is currently happening with the drow and the general rewriting of all the previously "evil" races.