Solid write up, nothing I really contest. I'll add a couple points.
I believe Grimme will encourage playing some of the less used spells, either because the other spell on the same value has just always seen 4 of, or because pulling your one copy of Puppet into play changes the game entirely while improving your deck.
Sight Beyond Sight also needs a special mention. Being free, moderate difficulty, high value, and it removing itself from play when chosen makes for a great spell with Grimme. Combine with Ivor xp1 and it becomes a major deck strategy.
Also of note are cards that unboot your spells. There may in fact be something to consider running Grimme with decks playing Gateway to Beyond (comboing Turtle Guard and Ghostly Communion perhaps?), Steele Archer xp1, and/or Stokers Saber.