Like control decks, midrange decks will gain incremental advantages over the course of the game, but where they differ is that midrange apply pressure to the opponent at all stages of the game, not just towards the end
I would expect to see Grief out of decks such as Jund, Deaths Shadow variants, Orzhov Taxes, and possibly even black-based combo or Reanimator decks
In the case of the Spellgorger Weird token from Ral and the Implicit Maze, you're being instructed to create a copy of a specific existing Magic card and the reminder text is giving you all the important information about that in case you aren't able to look it up otherwise
We've seen this template done successfully with the tri-color cards in the Khans of Tarkir block, such as Soulfire Grand Master
That means an average of one every five cards helps the strategy, which is far too few
Extort comes with Sorin of House Markov and Sorin, Ravenous Neonate, and it is just a fantastic way to make enemies in Commander