Present Arms swaps your library with another deck you own from outside the game and use that one instead ("library" and "deck" both refer to the same thing, but the former is used to refer to it in-game, whereas the latter is used to refer to it outside of the game)
I do think they want to slide back and forth through different expressions and play the one that suits their needs at that given time. Of course the Historic format was already unique to Arena as well, if technically playable with paper cards
Each of these represent solid win conditions in their own right, either because of the amount of counters they can stack or because of how much damage they can deal once they have counters stacked on them
Creating as many goblins as you can to fuel Krenko is key, from Dragon Fodder to Mogg War Marshal, combined with haste enablers, and effects to make sure they connect (like the flavourfully named Goblin War Drums)
Magic: The Gathering started all the way back in 1993
