@chubbyrain the powerless JacoDrazi strategy really only wants Thorn of Amethyst when Storm-based combo presence is high. With the rise of Paradoxical Outcome combo it was definitely a nice tool in the toolbox, but it can be worked around when deck building. Null Rod is by far the best disruption in the deck, followed by Chalice of the Void, so if you want to add more disruption you can play 1 Thorn and 3-4 Sphere of Resistance in the 75 (they don't all have to be main deck, which is important). Mindbreak Trap has been back in my sideboard for some time now (instead of Leyline of Sanctity) to help combat combo decks, but some number of Spheres can also be at your discretion.
The far more devastating effect of the Thorn of Amethyst restriction is to White Eldrazi. Thorn + Thalia was the basis for that deck to begin with, so I think now is the time for those White Eldrazi decks to widely adopt Null Rod/Stony Silence, as well as fully integrate Sanctum Prelate in to their builds, and change their manabase slightly to accommodate the necessary change. I played a fair amount of Prelate in the end of 2016 and early 2017 (in both Eldrazi and Junk Hatebears decks), and it is as good as advertised, if you can cast it on time.
If the DCI wanted to hit something from Workshop decks, but still leave other decks more playable, they should have hit Sphere of Resistance, as mentioned by Steve in the podcast. They followed this logic in Modern when banning Eye of Ugin, but leaving Eldrazi Temple unbanned (when Eldrazi Temple was the stronger card in all of the problematic Eldrazi decks). That precedent and logic left Modern format Eldrazi decks hampered and slowed, but still playable, as evident with current iterations in Modern of Bant Eldrazi and EldraziTron.
With the past 9 months of Banned & Restricted List Announcements by the DCI, and the ensuing aftermath, the most generous pundit could only claim that 2017 has been a year of questionable DCI judgement at best, and capricious or incompetent judgement at worst.