The cause of this is because 1) Slivers are incredibly popular 2) we haven't had Slivers in a main set for a decade and reprints are few and far between, so supply is low 3) Sliver Swarm did a bad job reprinting Sliver staples
Obviously I have nitpicks with individual cards -- I've been yelling about Temple of the False God only being good in decks that reliably land ramp and it's especially bad in decks with lots of color pip requirements -- but these are just nitpicks
While Misdirection being a blue spell meant it could easily redirect either red blast when they target a spell, the red blasts are modal cards that have their mode locked in
This could take several turns, depending on how good your hand was at the start of the match, where your cards lie in the deck, and how many cards you can use to eventually play one with Vigilance
Creature ramp: Solemn Simulacrum, Sakura-Tribe Elder, Wood Elves, etc