Is there a faction (minus Forsaken) who are still loyal to Sylvanas going into 8.3?

[mario710]

Still better than the Forsaken heritage armor quest in next expansion that will be all about atonement for ever serving under Sylvanas and seeking Calia's forgiveness.

Nope, this simply isn't true.

[Friendlyimmolation]

Nope, this simply isn't true.

who's alt account are you I wonder.

[Mehrunes]

who's alt account are you I wonder.

Boring alt account*

[Grazrug]

Nope, this simply isn't true.

Yes it is. Go away alliance in forsaken disguise.

[Eucep]

bold of you to assume that Sylvanas living would be disaster for the game, other than the other problems which people unsub for far before story.

Problem is it could go many ways. And one way I think is more likely then 'she will lead the horde to glory' is that she downright betrays everyone for her own sake, horde included.
With the current storyline I see a few potential lines:

Deep betrayal line: Sylvanas has indeed control over Jaina's brother and has him kill Jaina. Tyrande goes irreversable vengeance mode. In this line N'zoth likely gets beaten in 8.3 This line will probably pit Alliance against Horde again in 9.0 but even worse, likely resulting in the death of Azeroth. Which likely results in the full wow reset.

Doomed betrayal line: Sylvanas tries to use Xal'atat against most likely Alleria to get void power to 'control' or 'defeat' N'zoth. However her having been fooled in believing she has any control over the artifact ends up imprisoning someone else, maybe even Azeroth herself. In this line, N'zoth wins. Likely Sylvanas despite having been betrayed might use her alliance with Helya to lead the Horde survivors into the shadowlands. Likely in this line she is one of the few survivors among leadership.

Sacrifice line: Sylvanas with her undead/death alliance has all key things in position to stop N'zoth at the point he does not expect it, probably warding both Horde and Alliance against the onslaught by the powers of Death and Undeath. This requires a lot of sacrifice and she knows she can never make up for it, so likely is the final sacrifice herself. This one also can easily lead to a wow 2.0 as it likely leaves the planet near devastated unless the theory is correct that Azeroth now also houses Argus thanks to Sargeras' final act.

Blizzard line: Sylvanas tried to betray but gets stopped in time, still several characters die. She flees while Nathanos dies to protect her. N'zoth is beaten but then either Lich King Bolvar or the light becomes the next menace.

Yeah sadly I think last one is most likely as it keeps most of the usual status quo.