I don't think this actually addresses the problem with Companions, really. To be clear, it does make them all less generically powerful. But, it doesn't actually address the advantage they offer.
Consider this. Let's say your deck otherwise can run Jegantha. You didn't build your deck around it, you just happen to meet its conditions. Now, do you run Jegantha? Is it worth a sideboard slot to have a 5/5 for 5+3 sitting there for the late game?
I would argue it's still worth it. You're still getting access to an extra resource your opponent is not, and it's probably worth a sideboard slot.