While "draw until you have three cards" seems interesting enough, the drawbacks are very high
There are 33 main sets legal in Historic, with 16 digital-only releases to help flesh out the set and to introduce some unique cards that are not available in other games, not even Magic: The Gathering Online
Slash of Light in popular Magic: The Gathering formats Flash of Lights effectiveness varies with each popular Magic format
While both players drawing an extra card may seem like a wash, a mulligan impacts different decks in different ways, and has different consequences whether you're on the play or on the draw
The Rotom V alternate-art card has been selling on average for $60 and has even been fetching $75 on online auction sites
This universal catch-all has a very limited drawback, tossing the opponent a creature when its slain