No your not missing anything.
The most important thing about this commander is resource management to maxmize value. Teysa decks should basically be viewed as a machine with an input and an output. Therefor, they need to be as efficient as possible.
The primary objective of this particular list is fast paced token generation. Death triggers are used to support this primary objective.
Cards like
Massacre Wurm,
Yosei, the Morning Star,
Kokusho, the Evening Star,
Vindictive Lich etc etc etc are all super evil death triggers that are excellent to run with Teysa at the helm. However not in this mix. There is a few synergy problems with this list.
1. Recursion. Everything in a Teysa deck needs to be viewed from a standpoint of value. It is sheer blasphemy to run any ETB and especially death trigger LTBs with the intent of only a one time use. Yosei, Kokusho and the Wurm are NOT easily recurred via tools like
Sun Titan or the
Karmic Guide and
Reveillark loop. Recursion of these guys require mana pigs or other tools that slow you down.
Emeria Shepherd - 7 drop and only on landfall
Emeria the Sky Ruin - only once on you turn and requires you find a crap ton of
plainsDebtors’ Knell - another 7 drop and still only once on your turn.
Ravos Soultender - only once per turn and to hand not the field.
Etc etc etc... these are all excellent tools if you build a deck that focuses on death triggers and reanimation specifically. But this build focuses on speed and tokens.
2. Token movement. The main goal here is to fly under the radar and capitalize on token movement to have my machine produce the desired output.
A card like
massacre wurm will wipe boards,
anger people, and incur
retribution immediately. Orzhov and tokens has a fair bit of weaknesses. It does not give you much on hand to actively defend your self from anything tall or flying. Green Tramplers are scary. It has no anwnsers to counterspells from blue, or burn spells from red.
So, as a wincon, sure... maybe. Definitely not at any other time.
And finally, the death triggers in this list all
supply the overall strategy with value in terms of overall acceleration. Card Draw, Mana, and token production.
The wurm is a great card, but at 6 cmc, i feel its a bit high for a backup winncon, that supplies me no needed ressources for speed or acceleration if i draw it the early game or even midgame.