Newer cards like Smite the Deathless and Rebel Salvo follow this same pattern and target indestructible creatures in ways that most other removal spells cant
There are also some other interesting payoffs for cascade built into the deck, so youll definitely be able to make this strategy work right out of the box
For more information on those treatments, check out the Collecting Kamigawa: Neon Dynasty article
With the printing of Obosh, the Preypiercer, itll be extremely challenging for the type of red deck that has historically benefited from Experimental Frenzy to ever consider an even-mana card
The major issue with the Nightmare is it's templating that after it has been resolved, there is no window for my foes to destroy it until I pass priority
That said, your average Commander deck runs a decent amount of instants and sorceries, so my prediction is Arasta of the Endless Web will make ~5 tokens fairly consistently before its removed