Yes, Sable seemed both higher class and more intelligent than Alexis -- Alexis was more the narcissistic poseur, while Sable was the more crafty and clever of the two. (Part of that was the writing while, frankly, part of that came from the casting). And part of that sense of superior class was Sable's selfish villainy being motivated by a more-or-less sincere concern for the welfare of her children, while Alexis barely even had the pretense of that (at least until she returned to Denver and could use her now grown children as a weapon against her ex-husband).
In that way, Sable had a bit more in common with Abby: they were shapeshifting spiders and full of guile. Alexis felt always like a mere usurper, a scattershot and histrionic opportunist whose methods -- eventually -- kind of worked almost in spite of herself.
In fact, I've always wished Alexis had been a bit
more like Sable and Abby (and I get the impression Joan did too) because while the whore-made-good quality was part of Alexis' appeal -- that of the Mysterious Slut -- I would like to have seen at least some of her schemes result from a masterful sense of manipulation instead of simple good luck where her lazy tantrums just somehow paid off (a result of much lazier writing than COLBYS or KNOTS ever displayed).
And, yes, I think Alexis' ongoing enmity towards Krystle was based not just on Krystle being the newer, younger wife who now owned Alexis' ex-husband and mansion, but also was the result of Krystle's unnerving characteristic of demonstrating more genuine class (despite a childhood of poverty) than Alexis herself could ever quite muster (despite a childhood next door to privilege).
Alexis wasn't simply jealous of Krystle having Blake, she was just of Krystle being Krystle.
Alexis was wily enough to "get" the concept of class, even if she could never get it
for herself as
class wasn't the type of possession one achieved through the acquisitiveness Alexis understood. So she knew enough about it to know she didn't have it, which only fueled her efforts at overcompensation by draping herself in so much sapphire and sarcasm that it kind of mesmerizing.
So, yeah, the less-is-more standard of Krystle must have indeed driven Alexis up the wall.
And that's why Alexis symbolically shooting Krystle off her high horse so early in Season 2 was so genuinely tragic -- much more so than the series' general forgetfulness of the crime -- because the only way Alexis could kill Krystle's qualities was by killing Krystle herself.
That's another reason I was so grateful for Season 9: it explained why Krystle had changed, why the original Krystle was lost to us so early (even if that was actually due to hapless writer-producer choices only a couple of years into the program) so she could exit with some retroactive dignity just as Alexis' strategic superior, Sable Colby, blew into town.
It made the whole thing seem a bit more biblical, if only at the eleventh hour.