It would have really changed the vibe of the later seasons. With Spike gone, this would have led to a few different possible plots that I think would probably have all sucked in different ways:
- Briley becoming the endgame ship - I don't think I need to explain why this is bad. Riley is so whiny and insecure about the fact that Buffy is stronger than him and keeping him around permanently would really have undermined the show's "girlpower" message (not that existing canon doesn't, but that's a different topic entirely). Keeping Buffy with a boyfriend who takes out his insecurities on her and secretly resents her strength would be such an unsatisfying ending for her.
- We introduce a new love interest for Buffy - considering how every long-term relationship Buffy has in the show feels kind of like a narrative replacement for Angel, this would probably be a weak writing decision only beaten in terms of annoying-ness by keeping Riley around. Riley and Spike both reheat the format of "Buffy's older, experienced boyfriend who helps her fight monsters," with Spike also being compared to Angel due to being a vampire. And Spike is a very inconsistent character especially during the Spuffy arc, but at least Spike is a returning character and kinda sorta feels like picking up an existing plot thread rather than just sticking in a new character who isn't that original (I like Spike more than Angel as a character, but as far as writing quality he often comes across as "Angel but worse," and having a new character that no one is attached to fill that slot would be so incredibly boring).
- The only way I could see this not being terrible is if perhaps Robin was introduced earlier and we draw out the will-they-won't-they more... maybe we bring up the fact that the high school is in the process of being rebuilt in season six, which Xander has canonically been contributing to? Having Robin around earlier would let him be developed more; Spike being gone would drastically change how Robin's arc is written, but I don't think that's necessarily a bad thing, since the writers try so hard to justify Spike's behavior that it makes Robin seem petty when in reality his hatred of Spike is incredibly reasonable. I would also still end the show with Robin/Faith rather than Robin/Buffy because I think Buffy ending the show single is important to the themes, and I also think that showing Robin as more of a serious possibility for a Buffy love interest before having that relationship end amicably without doing a love triangle/serious conflict with Faith about it would be a really interesting and mature direction for the show to go. We've already done the love triangle thing, and moving on from that would be a good narrative way of communicating that Buffy has a more mature understanding of how to deal with relationship drama.
- We bring Spike back to life - it wouldn't be the first resurrection in the show, so at least it wouldn't be out of nowhere, I guess. This could be either really good or really bad, depending, but considering how everything after season five seems like the writers were drawing ideas out of a hat in a random order, I lean towards thinking this would be really bad. Either they bring him back with a soul, which could be good if it was a serious arc but would actually probably have been used as a cheap plot device to sidestep character development and make him a good-ish (he's still Spike) person for Buffy to date immediately, or they bring him back soulless and everything kind of happens the way it already does, which makes killing him off and bringing him back completely pointless in the first place.
- This adds to the tension between Buffy and Riley because, while Buffy does hate Spike, she disagrees with how Riley went about this, and this contributes to the Briley breakup before letting Buffy be single for the rest of the show - probably the most unlikely option on the list, because I really can't see them letting her go that long without a love interest, but it definitely would have been an interesting take! They break up, she gets busy fighting Glory, dies, comes back wrong, and then where does she go from there? She has to do a lot more introspection about how to find meaning in her life--her life, not her-and-her-boyfriend's life. This would have let them focus more on her friendships with the Scoobies and on the new status quo in the Summers' household, which would have been a much stronger way of showing Buffy's steps into adulthood. But this is highly unlikely, and it also means they probably would have ended the show with an even stronger implication that she will definitely get back together with Angel. Aside from my own dislike for that relationship, I like the ambiguity of him saying he can literally wait forever in response to her saying she's not done baking yet and doesn't know who she is going to be or who that will be with, and having that scene while there are no other current options presented to the audience for who she could end up with would make it a little too "they're soulmates" for me. I like that the show doesn't end with Buffy making a firm decision, and were there no other love interests on the table, the show would almost certainly have ended with her choosing Angel (or at least with the writers heavily winking at the audience to say that she will choose Angel without having Buffy herself say it directly).
I have very mixed opinions on this scene; I don't think it makes sense for Riley to do a fake-out staking in the first place, but there's something really interesting to me about showing him being this calculated and sadistic towards Spike. Buffy's current love interest, a character who is introduced in such a way that he is clearly meant to be cool and sympathetic, takes the time to plan out a way of committing an act of violence with the intention of making Spike believe he is actually going to be killed? By the time this happens, we are building up more and more the fact that Riley does not make great choices and seems to think he is right about everything, but this is a really bold step from a writing perspective. It is, I will be the first to admit, very stupid. But it also takes a character who was at most annoying at first and has him show murderous intent towards a fan-favorite character, which makes it pretty clear that the writers no longer care
that much about trying to convince us to like Riley. And I don't know that there's a specific moment where he starts to
become this person... it would be pretty easy to argue that this side of him was always there. So while I think the plastic stake is a really stupid concept, I like what it shows us about Riley as a character, and I think it's just weird enough that him staking Spike for real wouldn't necessarily get the same point across.
And overall I'm glad they didn't choose to kill Spike here. My serious reasons are listed above and my lighthearted reason is just that I like him (or at least like him too much to kill him
here; I think there are several points in season six where I think killing him off and then bringing him back in season seven could possibly work; although, as established, I think that the writers would have used this to avoid giving him character development rather than adding to it and am glad they didn't do that).
