My thoughts, as they have always been for the past few years, is to restrict workshop. I think a lotus (perhaps the most broken mana card) that stays every turn and just TAPS for 3....that you can play up to 4 of...is just insane. If we were to say "Workshop decks, and only workshop decks, are allowed to run 4 black lotus," everyone would think that was madness. Yet that's exactly what they do now, except the lotuses don't sacrifice themselves. I am actually against restriction as much as possible, but I think with a few key restrictions, you could remove a ton from the restricted list. Give shops back golem, chalice, and thorn (the later two also helping fish and eldrazi decks) in trade for workshop. That's a 3-for-1.
Not only could you unrestrict more, but cards like ballista become safer and there'd be no need to restrict it. It also opens design space to print further 4-drop broken artifacts. With 4 workshop, printing another golem-level power card is dumb, but with 1 workshop, it becomes a possibility. I understand workshop players love their workshops, but they could get back all the restricted toys plus many more to come in the future, if they'd be willing to go down to 1 and some sol-lands. I hear people saying 1x shop makes workshop decks unplayable...and yet eldrazi did just that with 4 thorn, 4 chalice, and sol lands very successfully.
Eldrazi even ran a 1-of golem most of the time, so it's not like 4-drops are impossible without workshop. Eldrazi temple was a "sol-land" that could only cast eldrazi...otherwise it was a colorless derpland. Without chalice and thorn, Eldrazi is essentially dead and fish took a big hit. Why are we okay eradicating a competitive budget deck and nerfing fish just to hang on to the dredge/FoW/workshop triangle that is Vintage? I'd similarly restrict bazaar for much the same reason....and would even be up for restricting FoW if blue became too strong. I think if you restrict the RIGHT card, you can avoid several other restrictions and stop constricting design space for new cards. Why this need to hang on to workshop if it means unrestricting all the tools shops lost already? Everyone sees picking off one tool at a time has had almost no effect on shops' dominance. All shops players grumble every time they have a toy restricted (yet blue has a massively long list of restricted spells, and shops players are mainly fine with that). Lose 3 workshops and get back all your toys and never lose another toy again...and get new toys printed. That seems the best course to me.
edit I just read the website posted earlier:
Looks like Demars copied my post, went back in time, and beat me to the punch ;). Says almost exactly what I said.