I don't have to, I've seen the final product.
Fine, I'll concede the point that recently, WotC as a company can't seem to create any of these setting-type products very well.
That's likely what you'll get from WotC though. The capacity of their current writers to create new ideas is basically non-existent. They'll pillage the old lore, change it (almost always for the worse) and dump it into the D&D Beyond trough for consumption.
I highly expect WotC to push this as...
There are lots of Dark Sun fans, much like myself, that just want to see the IP treated with the respect and care that it was in previous editions. Hell, I didn't play the 4e version, but the books were still very good and they added some neat ideas to the setting. And they didn't have to remove...
Well when I play Dark Sun, it's with fictional slavery, and it's always for entertainment purposes. It was front and center in Dark Sun 2e, 3.5e, 4e, and it should be there for 5e (#doubt). And just to be clear, nobody is saying real life slavery is good.
It's only a problem for some.
The city-states relied almost exclusively on slavery (with the exception of Tyr and New Kurn) for their economies and infrastructure to operate. Just look at what happened to Tyr when their Sorcerer-King was killed, and all of the slaves were freed. The city went...
Defiling worked just fine in the original boxed set. It was well established in its effect, just not really in it its implementation. The UA article however is a complete swing and miss.
WotC won't publish a book with prevalent slavery in it, especially one where the PC's can end up as slaves...
If Dark Sun is ever redone by the current writers at WotC, this is likely what we'd get. But considering WotC can't even get defiling/preserving right, and you can't make a faithful Dark Sun setting book without slavery, well, I don't see it happening.