Okay, I haven't read the issue yet, but from what I have read here, I have this to say:
If Joss had originally planned for Issue #40 just to be an epilogue or a set up for what's coming in Season 9, he had better re-think his plans, because there's just too much left hanging here to consider this to be an end to anything.
Angel, whether as himself, Angelus, Twilight, or whatever other persona you care to give him, is responsible for, or at least directly involved in, way too much death and destruction to just walk away muttering to himself. There has to be some sort of atonement for his actions, and it should be on a scale that makes the Twelve Labors of Hercules look like a weekend project.
What is the fate of Faith and the other surviving Slayers? With all magic expelled from earth, will there still be demons and vampires to fight, or can they all just go home?
Also, if magic IS completely expelled from the world, are we then to assume that Giles is permanently dead? (Almost certainly so, and while I'm sure that a lot of Giles fans will argue, he was the logical one of the original cast to die. His original role as mentor and father figure really isn't needed anymore. It does make any future "Ripper" series highly problematical, of course)
With no magic left, what is to become of Willow? Over the course of this season, and even in the latter part of Season 7, her entire contribution to the team was her power as a witch. Without that, what does she have?
As for Spike, if Tranquility's summary is complete, when we last saw him, he was in hot pursuit of Willow's vagina demon (god, but I just realized how that must sound!) headed off toward parts unknown. Why did that particular demon not get sucked away with all of the rest? Or did it get sucked away, and Spike got sucked away right along with it?
I can't see leaving all of that hanging, and then just have another issue not addressing any or all of it before the season ends.