No, it's going to be something people like about CoS that doesn't feature prominently in other properties. So, for example, we can deduce that it doesn't focus on Dragons, because he would have said "If you like Tyranny of Dragons..", it's not about Giants because "If you like Storm Kings Thunder...", It's not a mega-dungeon because "if you like Dungeon of the Mad Mage..." and so on.
You can also rule out Dragonlance because Chis is an "adventures" guy not a "rules" guy, and before you can do Dragonlance justice you need rules: Dragonlance specific races as a bare minuimum.
Well there you might have a point, although rule conversions for DL are nothing compared to conversions necessary for other settings (DS I am looking at you, my 5E homebrew true to 2e DS take on this did cost me some hard thinking on how to do it and I am still not sure on how to do psionics best).
Kender is just a Halfling with fear resistance instead of lucky and sleight of hand as inborn skill.
Imho you do not need draconians as a PC race (Because they are mobs) , but if you insist they can be deducted of Dragonborn somehow. Minotaur is a bit harder but reskin halforc and you are close.
What else do we have? Those Irda ogres, hope I did remember this correctly, well do we need these for the start? And the different elves are easy again.
Solamnic Knight is a bit tougher to do if you somehwow want to stay true, but somehow at wizards they think this is just another paladin oath or pruple dragon knight or cleric of paladine.
I disagree on all of that, they are iconic and certainly deserve their own character class, maybe a fighter with feats or so to depict the different orders.
So what else dragonlances, the melee damage they should deal requires a bit of brainstorming they certainly need to be toned down a bit, but maybe they act vorpal vs dragons or so.
Moon magic, this one is a bit harder, I would work with advantage neutral and disadvantage for spell saves and attacks here.
Ravenloft aka CoS only has been such a fast shot since they ignored loads of stuff , like spells which casting would be an act of evil inside Ravenloft, haven't read CoS but does it feature sinkhole of evil effects? like e.g. turning undead with disadv. etc. Also is there something like the powers check still? There was some UA about fear and horror checks, I used this in my own ravenloft campaign and it worked out quite well.