When I went to college at Boston University many years ago, I didn't study game design
Caltrops is also your ace in the hole, because it triggers The Incredible Hulk's Enrage ability, which can lead to endless combat turns and an infinite combo game win provided you've managed to give him Indestructible
If theres a choice between attacking with a couple Saprolings or not, it can be worth it to hold them back to build a bigger March (and can also be a fun way to bluff them into not tapping out for Teferi)
Copying big spells is all kinds of hilarity, whether its a nonlegendary creature or Jaheiras Respite (now requiring half the number of attackers)
The pressure game is superb, especially if you're not too fond of the partner mechanic.
Willow also scales his stats based on the number of lands you have in play, which makes him good value for mana even as he accumulates commander tax later on