I don't really know if it's command-zone worthy to build around, but in decks that want to reuse some Overrun effects or Elf decks that have some room to play with, I can see him making a big swing
This percentage shows your percentage as a player, that is, if you are in Mythic 85%, it means that you are ahead of 85% of players who are also in Mythic
If I were to build the deck from scratch, I would instinctively go for small critters and mana-ability-reduction to flood the board with cannon fodder
The four card limit applies to all of the cards in your main deck and sideboard, so you cant include more than four copies of any card across both, except basic lands
I started a few years back, deciding to collect one card for every pokmon