Zilliax was a decent heal for many classes. DH seem to be all about damage. Taunt seems like a good defense but they have tech to ignore taunt and many direct damage cards as well. We need more lifesteal or heal cards (LIKE ZILLIAX) so in 2 weeks, we have other classes than the direct damage demon hunters. Alexstraza was also super buffed with Zilliax removal.
We already have other classes. The same decks that were good before DH are still good, some are beating DH easily (looking at you Highlander Hunter). You’re seeing DH everywhere because it’s new, cheap and really good relative to how inexpensive it is right now
Priest is doing really well, too.