My bad, I meant Alleria, I’ll edit. Typing quick at work.
And yeah, I have them unlocked and have done the war campaign. Though I only spend about 5% of my actual playtime on alliance.
I’m going off of Lorthe’mar’s own words, he said he expelled them for tampering with the void and he was worried about the effect it would have on the sunwell. He even states there are a lot of dissidents in silvermoon. Some are happy with status quo, some want to go back to alliance, some are sympathetic to Kael’thas, some want to seek bloody vengeance against Jaina. He wants to work with all groups to promote unity, but he said the void would not be tolerated. And then a lot of their dialogue during the unlock IS all about how they are bitter that they were banished. They obviously got more face-time in BFA, but I think a lot of it was to give them a bit more identity outside of what they were first introduced with.
Which, would mean also needing to kick out a lot of priests, and there are a bunch of warlocks openly practicing. But like I said, hamfisted, and doesn’t change the fact that just doing High Elves, which were already introduced, dissident from current government of Silvermoon, and pro alliance, would have all gone over better with the community.
Especially the idiocy of the whole alliance completely trusting Alleria and the void elves when both horde and alliance are currently fighting against the old gods which were created by the Void Lords. Beings so terribly evil that the burning crusade was created.
Edit: I went and looked their lore up on the wiki. I was not Lorthe’mar that kicked them out, it was Rommath.
But: " A blood elf magister, Umbric, was determined that the sin’dorei would never fall prey to their enemies again (referring to Arthas and Scourge). Convinced that the void was essential to the defense of Silvermoon, Umbric and his followers delved into it against the wishes of Quel’Thalas’ Grand Magister, Rommath. Eventually, Rommath had them banished, reasoning that any who treat with the void pose a danger to the Sunwell, and Umbric led his followers south to the Ghostlands to pursue their research."
" Returning to Azeroth, Alleria was forced to face several hard truths, among them her people’s alliance with the Horde. Although the rulers of her kingdom had never held the loyalty to the Alliance that Alleria herself had come to feel – indeed, Quel’Thalas had rescinded its membership in the Alliance under her former king Anasterian’s rule, and relations had only worsened since – she was determined to see Silvermoon stand again on the Alliance’s side, and was certain that her people would shrug off the Horde if given the choice."
“Alleria immediately offered her aid, wanting to help her transformed kin understand and control their new forms and powers, and Umbric, apologizing for his arrogance, happily accepted. Feeling that Silvermoon had turned its back on him long ago, Umbric swore his allegiance to Alleria and the Alliance.”
So you are wrong too, it wasn’t the void elves trying to join up with the Alliance due to political dissidence with Silvermoon. In fact, they were persuing better ways to protect silvermoon until they were then kicked out. It was at Alleria’s urging since they had been “abandoned” that they agreed to join the Alliance.