6 Thoughtseize Stepping out of the sideboard, Thoughtseize is the first discard spell on the list to see mainboard play
Regarding Sword of War and Peace and Batterskull, the metagame is right for maindeck artifact removal
Paying one mana to bypass an entire casting cost is why reanimation remains one of the most feared strategies in the game
The most obvious of these factors is the synergy of haste with Saproling Burst, which was known to some as "The Fix." That extra turn almost doubled the strength of the Burst and made it hit for the full 20 damage in only two turns, which would normally mean a kill on turn five, or turn four if backed up by a Blastoderm
This process will be used for all future Universes Beyond sets, like the upcoming Spider-Man and Avatar: The Last Airbender sets, which will be similarly balanced and legal for Standard and other formats
But it is also powerful, flexible, and opens up design space in exciting ways