While at MagicCon Vegas in late September this year, I spoke with Mike Turian, product architect for Magic (though his role while M21 was in design was principal product designer, according to his LinkedIn), and he confirmed that for M21 the design for showcase cards was intended to keep the text boxes clean and uncluttered, kind of like you would see in simple but powerful spells with only a few words on them, like Wrath of God or Counterspell
New black- and white-bordered cards are legal as of the Prerelease event for the corresponding set, or in the instance of supplemental products, like Commander decks on the release date
Yes, Im ignoring the 30th Anniversary Edition printings of the card on principle
Board complexity tends to boil down to several categories: First is the subset of cards that affect other permanents on the battlefield
Cards like Secure the Wastes, Reverent Hoplite, and even Myr Battlesphere have been conscripting hapless soldiers since the dawn of time in the mid-2010s
That plays quite well in a Voltron-style build where you make your Tanazir bigger and also makes your Hydra and similar X creatures bigger as their base is normally 0/0 so you get a +4/+4 effect to them without shifting the power of the founder of the Quandrix School
