The top 8 Joust Decks at GenCon, and the Final 4 Melee ALL featured the appropriate "fury of ..." plot. Obviously not all of those would have been up against opponents with the appropriate house-card to use the special ability, but there's a chance.
On the other hand, if there were to suddenly be a new house, that house would be guaranteed to be safe from that, and various other cards which specify targetting a certain house card, as they didn't exist when the cards were printed.
With the neutral house cards, players get this protection, but with a trade-off of having to pay a gold penalty on any non-neutral characters. It just seems like creating a whole new house would give that house a massive advantage, as no-one else would have specific abilities targetted against them.