I don't think it's as simplistic as viewing Bangel as either puppy love and OTP. It was first love - first serious love and they have a soul connection, a lasting connection but that doesn't mean that they are the great star crossed lovers destined to be together IMO. First real loves are not insignificant but they don't generally last. I don't buy the narrative you only ever love one person and that's it I think she loves both Spike and Angel in different ways but equally. As she points out it's not as if Bangel was always healthy either - 'what was our highlight 'when you left me or when I killed you?'.I don't think it's a retcon of Buffy loving Spike. I think it's an interpretation.
Kind of like how some viewers interpret Buffy and Angel's love as a puppy love therefore it does not equal real love. Well that goes against what Joss has to say about Bangel because he in fact says they were the Romeo and Juliet love- which in the end is still love.
Maybe Buffy did love Spike, maybe she didn't. It really comes down to how you interpret it, even if how you interpret it maybe was not the intent of the author.
I interpret Buffy's "I love you" to Spike in basically the same way Spike does - no she doesn't but that was a nice thing to say to someone who is sacrificing their life to save the world. I do believe on some level Buffy cared about Spike. Do I think she was in love with him? No. I think what Buffy told Angel was true. "I feel for him." Because she did, but those feelings were complicated due to a multitude of reasons including Spike being soulless during their sexual relationship, Buffy being extremely depressed during their sexual relationship, Spike just now getting his soul back, Buffy having to fight yet another apocalypse, and Buffy still having Angel in her heart. Spuffy's complexity is what makes them interesting even to this Bangel right here. I like that what they have is complex and ambigious. I like that it isn't a love of the ages because not all relationships are that. Some relationships are just something you needed in the moment. While I find Spuffy unhealthy and toxic on many levels, I also find them incredibly rich to view because it speaks to how so many people end up in relationships that are bad for them but yet somehow they are still getting something they need from that relationship. Spike is getting recognition and Buffy is getting an escape from feeling so hollow since she came back from the dead. But not once do I ever view what they have as love- on either end no matter how many times Spike may say it. I seem to have went off on a tangent so I'll just end it here.