The main issue I raise with this is that now you are literally negating the mana denial strategy. Why would an opponent care about anything you're doing if they are holding their "remove whatever threat I want at any point" cards and can proceed with their normal gameplan? I can appreciate the frustration of being locked out of a game of magic (because I spent years focusing entirely on that goal with Stax), but right now it seems like some of the stronger Mentor lists are already focusing on building mana and using 1for1 removal to deal with any real threats a Shop player can produce. Spheres are annoying, but they can't kill you. Channel-Shatter would upset this dynamic by offering incredible flexibility for almost no opportunity cost.
Its not 'negating' a strategy. Its countering a strategy. Just like the mana denial strategy negates another strategy. Its something that's been able to be dealt with at acceptable levels until recently. But now with basically 1/3 of the shops deck being related to mana denial (10 sphere, 5 strip effects 4 revokers) and a more aggressive clock (ravager, fleetwheel, ballista) its gotten to the point that the opponent being denied mana needs better, more efficient answers to compete.
Thank you for making this point for me. If we can have Cage, Priest and Rest in Peace come out to counter Dredge/Oath, we can do the same for: 1) artifact tax effects, and 2) blue cantrips/card draw.
You also raise a good point that I was being too narrow in describing the prison effect of Shops. I neglected Wasteland, Strip Mine, and Revoker.
Here is what I believe:
- The current best build of Shops is Aggro-Prison, but it doesn't have much of a long game.
- It has gotten too powerful relative to the meta.
- An untaxable (but still Revokable) artifact-removal spell wouldn't destroy the archetype in the slightest. In fact, you can still Shop, Mox, Revoker (on the Cycling/Channel/Bloodrush ability), and Sphere on Turn 1.
- Such spell should be Green for color balance (or maybe Red, but that makes it easier for Jeskai Mentor to use, so I don't like that).
- Such a spell might encourage greater diversity of Shops builds.
- Such a spell might allow for one (or both) of Lodestone and Chalice to be unrestricted.
- Unrestricted Chalice would put a greater check on cantrip Blue and PO decks.
More broadly, my personal desires for Vintage are as follows:
- Greater viability of a greater number of archetypes--particularly in Black, Red and Green-based archetypes. I care about color balance.
- No deck (or "Pillar") is more than 25% of the field, and it has a Tier-2 or higher deck that destroys it (i.e. Dredge for Shops before Ballista and Ravager made that harder).
- More thoughtful, polite discussion in Facebook groups, TMD and other social media and less personal attacks, so that we can manage to look slightly less ridiculous. Especially considering that most of us are (I assume) older than the average Magic player.