Honestly after looking at what the Dark Elves are bringing to the table with Lokhir Fellheart, I want to see Dark Elves released next. The ability to have a portion of your army having Flank, and the Cloaked in Darkness command card..That is a nice counter to the Dwarf, Empire, or High Elf Gun lines, at least for a round.
The Verminitide will make rushing the Skaven hero or any other skaven heroes a gamble, or likewise, a nice suicide unit to rush in and then use the small AoE effect of the card. That might see more use after the Skaven get their focus, and there are Rat priests, so the potential loss of a hero is minimized.