Spike and his soul
The whole thing was very strange. Yes, Spike with a soul = Angel Jr., boring and would ruin so many perfectly good prophecies! ‘Wolfram and Hart’ over in LA will be very confused. Also, getting a soul is supposed to be a punishment. Well, OK, one can argue that cave demon was devious and with a cruel sense of humor. I wonder will Spike’s soul be detachable, like Angel’s, and what will be the trigger? Moment of absolute misery? Moment of quiet boredom?
Then again, making Spike human would be even weirder if you stick with the canon. Angel is supposed to work for many years, helping the helpless and averting apocalypses, and only then Powers will turn him into human. Spike only killed a bunch of demons, which he used to do every day before breakfast, and rolled in bugs. Making him human after that would be just too unfair.
In any way, what Spike and Buffy should do is make a deal with the cave demon and start shipping all Sunnydale vampires over to Africa for rehabilitation and reintegration into society.