All fair points, however Sulfur Falls isn't in standard anymore so that wouldn't work.
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I like the deck, however you should add 4 Steam Vents and take out 3 Mountains and 1 Island for it. You should probably also add The Royal Scions to the mainboard.
I personally might drop a Jace, the Mind Sculptor for a Liliana, the Last Hope, however that might just be me. I feel two Jace, the Mind Sculptor are enough in a Modern deck. However, I think your idea is pretty cool to add the Plainswalker aspect of Grixis Control. I would like to see how your sideboard would turn out for this deck if you ever decide to make one.
Tupperware sounds fun. I like the use of recycled cards like Censor and Scarab Feast.
Thoughtseize is better than Inquizition of Kozilek in Death's Shadow decks, however Inquisition of Kozilek can still be run. You should put in at least two of them. You probably should add Street Wraith for a better Death's Shadow filter. It is ran in every Death's Shadow decklist. I was going to mention you not running Batterskull... But honestly why would you run it in a Death's Shadow deck? I am glad you didn't. I think this is a fun deck idea with your Stoneforge Mystic's and Death's Shadow's. You should add a sideboard.
With diversity between slowing down not just your opponents instant and sorcery spells (like control), but also slowing down artifacts (especially when four color whirza and paradoxical outcome are top in the meta) it can be a good sideboard matchup against certain modern decks. I don't think Dovin, Hand of Control can always be sideboarded in your modern deck but it could potentially fit in a midrange and probably in a control sideboard that runs either (or both) of your azorius colors (assuming there is enough space to make the card fit comfortably). Just my thoughts. I agree with Crouch312 however, make sure you test it out first.
You should run Night's Whisper over Sign in Blood because of the black devotion it costs. Blast Zone can't tap for black, but it can tap for colorless so you can still cast Night's Whisper.