To focus on Lurrus again, mirror match formats are often high skill level. I suppose part of the reason I am trying to figure out how to "fix" vintage is because leaving it as the lurrus format is a pretty radical change. The other major concern for me is if Lurrus congegates on a single deck. This seems likely to me based on past experience with constructed metas. If multiple Lurrus shells exist then I'm less sure the card needs to be addressed. Adding a cheap legend to the list of cards you need for vintage isn't the end of the world.
@evouga Well let's look at the possible cases. Either a) the hatebear companions suck compared to the actual do stuff companions, b) the hatebear companions end up far more powerful than the do stuff companions or c) the hatebears end up perfectly balanced with the do stuff companions.
In case a) and b) clearly the problem is not solved. Case c) seems to be what you're focusing on but I'm afraid wizards' record of printing cards to deal with problem cards is very poor. They either push way too hard or not hard enough, so I think case c) is incredibly unlikely. Combine that with the fact that vintage would just be lurrus dominated until wizards got around to printing more companions, I think the idea is kind of fun to theory craft about, but practically speaking a total nightmare for vintage.
I've never seen a deck be this dominant in any format and then later had the format stabilise on its own. Maybe someone else with a better memory for constructed magic has an example of that?
These early Lurrus numbers seem to be around 75% of the meta, which considering the number of people who won't have the dime to drop on a Lurrus compatible deck is a terrifying percentage. If Lurrus has a 60% winrate against non Lurrus and also composes three quarters of the meta then taking anything but Lurrus into competition would be like flushing money down the drain.
Due to the very nature of the card and the format I find it hard to see how to build to beat it. You have to compromise deck composition a truly absurd amount to compete with a card they have 100% of the time. In other less streamlined lower power level formats like Modern Lurrus is just a strong 3 drop they always have access to. In vintage Lurrus's power level is much higher and he costs much less.
I do however think there might be another option than banning, and one I personally would prefer. As an aside though I think Companions are a huge mistake and fun only in limited formats. Why not try unrestricting an number of cards? Shops pieces in particular, but also maybe other cards that won't fit into a Lurrus shell like Flash, Dredge pieces, Ironworks, Mentor, Narset (lol), Necro, Karn? Seems a lot more fun than the banhammer and to some maybe more in the "spirit of vintage."