This trio of abilities is very strong in Gruul, because Gruul is one of the most creature-centered color combinations out there
Darkness and Metal types was introduced alongside the corresponding Pokmon Gold and Silver video game, the Dragon-type was introduced in the Japanese Dragon Selection set
While keeping your multicolored card count relatively high will make your Niv-Mizzet draw more cards on average, it may very well make the rest of your deck weaker
You can quite easily build a deck that profits off destroying your own enchantments just as easily as one that removes opposing enchantments
There is, in theory, a world where you could run Sunbird Standard, craft it with a white and a black card, and then use it to infinitely reanimate creatures with Alesha and infinitely attack in the combat step, but thats an insane amount of hoop-jumping for a mid payoff
Fitting function to form, a lot of Magic cards in the upcoming Final Fantasy x MTG crossover are, or care about, equipment, which is the usual way in which Magic portrays weapons