Pioneer generally lacks explosive early-game starts, and Arcbound Ravager would open up faster decks in the longer run
Not awful but far too low threat to really make the cut at that price range
Gimbal, Gremlin Prodigy wants you to amass a collection of artifacts with different names then pays you off by making Gremlin artifact tokens with trample
I believe this is valid because silver border, now acorn, gives the entire team, design, play, world building, art direction, marketing and everything in between, artists, players, and article writers a chance to go out to the very edges of what the game could do
If you need to catch up, you can check out the previous article, on card rarities, or start at the beginning with The Basics