It's not perfect, as you can miss, but we've found that four is a good number, where you hit a vast majority of the time
The additional tokens are still exiled at the end of combat, but you get a bunch of extra pressure
The second problem is that consumer faith in Wizards would be majorly shaken should twenty years worth of cards suddenly become worthless
If your goal is to fill the graveyard as quickly as possible, Golgari Grave-Troll is one of the best ways to do it, allowing you to skip your draw step to instead mill six cards and put the Grave-Troll into your hand
Furthermore, Archaics are returning, and while the one we've shared above is colorless (same as previously printed Archaics), Wizards of the Coast has teased that recent events in Strixhaven may have altered some of the soon-to-be-revealed Archaics powers and color-typing