Workshop is certainly a power 9 level card. More belonging on the P9 than Timetwister (in my opinion). However, there are a lot of ramifications of restricting the card. If you reduce it to 1, you seriously hurt Workshop decks, Two Card Monte, etc. Yeah, there are other "Sol Lands", but they come at generally a huge restriction. Ancient Tomb hurts you, City of Traitors go away as soon as you play another land, Eldrazi Temple is only usable in an Eldrazi dependent deck. Workshop has it's own inherent restrictions with it being only able to cast Artifact spells.
I'm not exactly excited at the prospect of playing against 4 Chalice of the Voids. I think that is a very dangerous proposition to make, especially as @Brass-Man said, when you team it with Eldrazi. 4 Chalice of the Voids would also basically kill Paradoxical Outcome decks. At least, make it very fringe. I think the last six months or so have made it much more difficult to unrestrict that card (and I was one that called for it to be unrestricted, so hypocrite maybe?). From a personal standpoint, I think Chalice of the Void is way more "unfun" card than any taxing effect. That's just a personal opinion though, take it or leave it (though this whole message is a personal opinion).
But going back to Workshops, let's say WOTC does restrict the card, what do you honestly do to replace Workshops? Okay, you have 3 open slots, but three incredibly important slots. I don't think it's as simple as putting in other "Sol Lands" to make up for the loss of Workshop. The value of Workshop to the curve of a Workshop deck cannot be understated. I would be very hesitant in playing cards like Wurmcoil in my sideboard as an example. Not to mention Triskelion (as a 5th Walking Ballista), or any card that costs more than 3 in the deck. The same thing happened when Lodestone was restricted. It wasn't as simple as slotting in 3 new taxing effects or more Phyrexian Revokers. Every card in the deck would have to be evaluated again.
That doesn't even account for the monetary ramifications of restricting the card, but I'll give in and say I don't want WOTC to make decisions based on that.
On another point. I don't think people are crazy for suggesting it, or even necessarily wrong (though I do disagree), I just think there is a lot to consider even on the mere thought of restricting Workshop.