I'll restate my position that I don't think Arcane Wonders needs to react to this too quickly. Only if it becomes a long term problem should they take action. I personally don't feel that HoBS is overpowered. Good, yes, but not overpowered. I've always thought it should be at least spell level 2 (if not 3), but oh well, done is done.
Just because HoBS is showing up in a lot of builds doesn't mean that something needs to be done about it. LOTS of cards show up in most/all builds, like Teleport, Elemental Cloak, Dispel, Battle Fury, etc etc. Just because a card is used a lot doesn't mean it needs to be nerfed.
I'm of the opinion that "problems" like this need to fixed via new cards. The Forcemaster vs Warlod expansion went a little way towards creating cards that deal with conjurations, but didn't do a good job of it IMO. Cards like Earthquake fall short of the mark by being far too weak in how much damage it can do to conjurations (should have had an extra die and been critical damage), and cards like Akiro's Hammer are just too slow, too expensive and too fragile themselves.
However, other cards can be made in the future that can help mitigate conjuration effectiveness. I hope they don't go overboard in creating cards that are too good at taking out conjurations, because then conjurations would quickly become liabilities rather than assets.