I've already covered a vast majority of the cards on the constructed list between my best instants and best card-drawing cards articles, so anything I might have to say about 50-60% of the cards on this list would be redundant
While some decks can become obsolete from one week to the next, they can also make a comeback after a ban, a reprint, or a powerful new card
in fact, instants in general are out
In just a few years, this card has already risen to become one of the most desired and valuable promo cards, and it will only go up more as time passes
You don't get to look at the cards in your library, but if you happen to know the position of a card in your library for example, you know what you scried to the bottom of your library with Opt, or you cast Approach of the Second Sun last turn you can use that to your advantage and make sure you draw it when you need to
Adding cards with abilities usually associated with another ink color would fill some big holes, especially when it comes to the ink ramp