Yeah 22 star dark boss accessories are BIS but super unrealistic. And to even get the dark boss accessories you'll need to be strong enough to fight the bosses so you'll have to have something else in the meantime which would be SW and Gollux stuff.
I think the way to look at these is just the base stats of the item? So SW earrings have 10 all stat, Superior pendant has 28 all stat and 5 m/att. SW pendant has 34 all stat and the Superior earrings have 15 all stat 10 m/att. So from here if you ever want to transpose to SW, then SW pendant is the better option. But if you already made a transposed SW earring then it isn't a good idea to make a SW pendant just for a tiny bit of stats.
I guess another thing to look at is the transposing options. I can't really remember if there are any other options for pendants other than the Dominator pendant so I'll just assume that's the only one. SW earrings on the other hand has the level 140 option Meister earring as well as level 150 options from Kritias and Oz. Based on my SW earring and SW monocle (I used Kritias earring and Pap mark), the difference in stats is only 2 all stat and 1 m/att. This difference is from the 16th stars of the Kritias earring and Pap mark.
So basically SW pendant comes out on top and you have to make one anyway unless you get carried, get a drop, get super lucky and insta 22 star the drop and now have no need for SW pendant or earring.
Instead of needing to deal the damage with the bind itself to gain additional bind duration, I think it would make more sense to increase the duration based on how much damage is dealt during the bind. Currently the additional duration mechanic is useless because binds are not extremely damaging skills. As a result you will never be able to get any additional duration unless you don't need the bind because you are already able to destroy a boss.
If binds were changed so that you gain duration based on how much damage you can deal in the initial 10 seconds, it would be much more useful than it is now. This would also allow all binds to compete with Kanna binds as their bind is currently very overpowered compared to the rest.
You should make a post in the bug reporting section. I'm a bucc as well and the skill works fine for me. Although I got the skill after the maintenance if that makes a difference.