mtg banned modern cards This and Restricted Announcement is a Joke Seven Cards Banned In Standard

While this is unlikely to stop a game-ending threat, being able to stop irritating early-game plays for just one mana is not to be underrated

Enchanted creature gets +1/+1 and has "Whenever this creature attacks, scry 1.") You don't choose a target for Spellbook Vendor's ability at the time it triggers

This will mostly be down to preference

You can treat a learn card as a card that has some minor value effect like draw a card or create a token that can tutor for a lesson card from your sideboard

The Good Of all the face commanders, Y'shtola, Night's Blessed is my pick for the overall most powerful if properly built around: it's an absurd card draw engine and finisher and lifegain all rolled into one