Nadu's ability is incredible, so long as you can create new creatures, you can constantly make use of it
For certain Commander players, immersion-breaking power isn't worth it, even if these decks can win them many games with the overwhelming power of artifacts, +1/+1 counters, and living semi trucks that roll out and attack for lethal.
On average it is the second best removal spell in all of magic and there is a fair old gap between 2nd and 3rd
When Unwilling Vessel dies, create an X/X blue Spirit creature token with flying, where X is the number of counters on Unwilling Vessel
Flying U, Sacrifice Siren Stormtamer: Counter target spell or ability that targets you or a creature you control
Gaining Hexproof is also super-relevant, as it turns off direct damage effects, discard effects, and a lot of graveyard hate all in one swoop