A useful Rule 0 explanation can be as simple as: "My deck is an upgraded precon, has no fast mana, and can win with a three-card combo after turn seven." This would tell the table far more than simply saying, "It's about a seven out of 10." Rule 0 can also be used to modify parts of the format
Four mana is a lot for a creature tapping for mana, but this makes up for it by tapping for lots of mana
That's what head designer Mark Rosewater seemed to suggest earlier this month anyway, as he recently claimed that Universes Beyond isn't "an endless well", and that there are a finite number of franchises to cross over with that will be popular
The flavour text is also a huge strike against the card, presenting the Romani people as some kind of mystical and mysterious people, othering them in the text
Ouroboroid then starts to turn your early game mana elf into a threat incredibly quickly
Originally meant to be the fixed Force of Will, Force of Negation accidentally dipped its toes in Modern Horizons juices for too long and instead went on to simply become Force of Will #2