My thing is that people should have various options, rather than be locked into a particular Dark Sun theme. Someone that started a Dark Sun campaign in 1991 would have been very surprised about how the Prism Pentad ended in 1993. Sure, the DM and the players don’t have to go along with it, but may they feel obligated to do so despite themselves.
The 1991 Dark Sun campaign is a very different beast from the 1995 campaign towards the end of the Dark Sun product line. What I am saying is that the various ‘Dark Suns’ should have equal standing. That did not happen in 3E Dark Sun. It was Free Year 10 or the highway. You can say that people had the option of starting their campaign any year they wanted, but as far as athas dot org is concerned, that option was not supported at all. It needlessly split the Dark Sun community.
4E was a different beast altogether (which caused another split in the community, although not only the DS community). Although the setting was reset to the period after Kalak’s assassination, the cosmology was revised to fit into the 4E standard. Inexplicably, half-giants disappeared, replaced with goliaths. Templars were warlocks, instead of clerics. It turns out that there are a lot of people that like warlocks as templars - of which I am not necessarily one. But because people like them, and because I believe in giving people options, I made a warlock style templar. I proposed this modular technique in my call for Mysteries of Athas (and here and here). I am proposing a win-win scenario when these matters are always presented as win-lose.
I thought Paizo did a pretty decent job of restoring the Sorcerer Monarchs in their version and I think it would be hard to do a better job. Since the PCs did not witness any deaths, nor can they get a definitive reason for the missing Sorcerer Monarchs besides an omniscient narrator telling them what happened in the metaplot, it should be OK to hold what happened open to interpretation (if it even happened at all).