The issue with San’layn being hit with the villain bat is of the types of undead, they’re one that seems to be an outlier with them being in a Forsaken/Death Knight position and having potential to be something much more.
In thinking of the Scourge, most of them are just your typical undead that you see with a cool sounding name, usually evil without a cause. Yes, a lot of them use living while others are corrupted with such fashion, but it isn’t really something you think about with most beings like skeletons, liches, or ever some of the Necromancers. Things like banshees are enough monster like that you see some semblance of what they were, but aside from rare exceptions, are just undead beings that exist to look cool and freaky for you to beat up. A lot of undead you deal with have the depth of a rain drop on concrete.
With San’layn, however, they use to be former blood elves that are in a Forsaken/Death Knight situation. They’re beings that you’d think would have gotten their free will back by now, with Arthas gone and the Helm of Domination destroyed. Thus, when you see them pop up twirl their mustaches, it feels a bit off and isn’t something that could’ve been much different with another undead like a lich or so.
Yes, not all San’layn would have high moral fiber. Same with Forsaken. Some are corrupted, gone insane for various reasons, obsessed with power, want to take advantage of the situation for their own gains, and so on. However, for San’layn specifically, it shouldn’t be all of them. Moreso when they were forced into undeath and were controlled to a certain extent.
Not to mention that we have seen various undead gain their free will back. Ghouls, geists, liches, and banshees among others have undead have gained their free will back. Yet San’layn still are acting evil for the sake of it?
Unless there is something up with their Vampyr curse, I see no reason why there couldn’t be San’layn who have regained some semblance of their actual selves. If the curse has an effect on it, then that sounds like a cool questline to research and see if you can break that part of the curse. They’d still be vampires and all (as they should be), but it would be better for them as a situation similar to the Forsaken or Death Knights than just generic members of the Scourge.
They also have a lot of potential, which I’ve talked about time and time again. Lore, storylines, NPC’s, aesthetics, and so on if they were fleshed out. Not to mention that playable Horde San’layn would likely be popular and something unique as their own race.
It’s a shame that we haven’t run into San’layn that aren’t more friendly so far. It’s likely some are out there, especially since how we keep running into Blood Royalty we haven’t seen before. Not to mention the missing Blood Princes.
As it stands, San’layn as your typically villain for whatever context just seems weird at this point without any good-aligned San’layn also in the picture. It also doesn’t feel right when you think more about them, and it’s not just because I want them as a playable Horde race.
As I said, I see them in a bit of a Forsaken/Death Knight situation with them being former Blood Elves caught up with being mind controlled by the Lich King and having a curse placed upon them. Makes me wish more would be done with that as opposed to making them as jobbers for questlines.
24 days until the next expansion is announced! 
