[First of all, this post is not meant to raise your blood pressure or cause you to reply in hasted hate. Just an open discussion on the repercussions of restricting an iconic card, and why I (nobody of any particular power), think we shouldn't].
We're all tired of B&R discussions, so I thought I would approach one from a different perspective. I've done a lot of thinking about the current Vintage format. I personally don't have a ton of issues with it, but it does seem like the worries of "critical mass" are becoming a little more pronounced.
I think there are a handful of different player types in Vintage.
1.) Some players look at the cards as nothing more than text, numbers, and ratios. To them, cards are nothing more than a variable to put into a formula.
2.) Some players hold older cards in reverence. They care about the types of borders, the art, the history, and maybe even the prominence of certain cards.
3.) Some players, maybe players who began online, might consider all cards equal. To them restricting a Paradox Outcome is no different than restricting a Bazaar of Baghdad.
4.) Some players only care about the variety of decks in the format.
5.) Some players want a format (and decks) that allow them to leverage their skill to a great degree.
6.) Some players care about a "balanced format" (with varying definitions of such)
7.) Some players might only care about their pet deck and its viability.
Even in competitive Vintage, there are plenty of Johnnys and Timmys among the Spikes, so it is hard to keep everyone happy.
Relationships
My issue with restricting Workshop is I think that older cards should be preserved as much as possible. My favorite aspect of Vintage is the ability to form long-term relationships and experience with the same cards.
From an intrinsic perspective, Workshop is no different than a Ballista, but from a historical perspective, a new card like Ballista has no long-term value, is too new for players to form a relationship with, and as a new printing, is a way for Wizards to test limits, without upsetting the player base. Many players will disagree with this, but I'd rather restrict multiple cards and keep the Workshop engine in place, than preserve the existence of cards like Hangarback, Ballista, etc.
I know many people will quote the cost of the card, but I don't feel like that should be a primary determinant.
Others will claim of an exodus of shops players, and this is a real threat, and while I don't think the DCI should be held hostage, losing any % of Vintage players is not something to ignore either. Especially these days, as the re-buy in for paper vintage is so impossibly high.
I do think that older, iconic cards should be held to a much higher standard. Restricting Workshop, in my opinion, is akin to restricting FoW or banning Ancestral Recall.
Flavor
People claim that adding a City of Shadows, or reworking your mana will nullify this restriction, but I don't think that's the case. Workshop decks (currently) have zero manipulation. Without playing Expedition Map, or something similar, seeing your singleton Workshop will be a rare event and will take a ton of flavor out of the deck. I personally bemoan the amount of "new frame" cards in shops decks as it is, this is not a deck that has stayed consistent over the last few years and has gotten more and more modern. To essentially remove an Antiquities card from the deck, takes a ton of the flavor out of Vintage. Much like Mana Confluence replacing City of Brass. But the flavor argument is a weak one, so that one doesn't bother me as much.
Frequency
Blue players often forget that due to manipulation, it's not uncommon for them to see an Ancestral and/or TimeWalk multiple times a match. With a single Workshop, seeing it once during a match might be an cause for celebration.
I know we've been talking about Critical Mass in Vintage for years and years. It appears that Vintage decks have pretty arrived a that point (interestingly enough blue and shops at the same time). There is no correct answer to what is the proper way to guide the future of Vintage. Some people are okay with it turning into Standard/Legacy with moxes, and others would like it to more resemble Old School. I'm sure thoughts about Workshop probably parallel those players bases.
This isn't meant to be an overly-articulate post, or even a persuasive one. I know everyone has drawn their lines a long time ago, but I do think that some people overlook the importance of Workshop to the Workshop deck. As I said before, this is like restricting FoW or banning Ancestral.
Lynchpin
I don't want to speak for Shops players, but I have spoken to quite a few. Many of them have enjoying playing various Shops builds over the years, and I would guess that most Shops players can stomach the loss of various Shops toys. I can't imagine too many emotional attachments to Ravager, Tangle Wire, Ballista, or even Thorn (as long as the deck stays competitive).
However, having to go back to the drawing board and playing a shops deck without shops, is not a journey that many of us would be very interested in. Restricting Mishra's Workshop is not "letting Shops players still play with Shops". Sorry, I just don't agree with that.
I have no problems agreeing that Workshop is an obviously broken card. But I do think it needs to stay in the format as a four of until we've run out of other options.
Note:
This is not meant to be an incendiary post or illicit incendiary responses. We all play Magic for various reasons, all of which are correct.